chore(docs): fix broken anchor tags across versioned docs (#21697)

## Summary
- Fix 6 types of broken markdown anchor links across 20 files in
versioned and source docs
- Add missing `## 4.1.0-rc.2` version heading in migration notes

### Anchor fixes
| Broken anchor | Fixed anchor |
|---|---|
| `#after-expansion` | `#private-functions-externalprivate` |
| `#private-functions-private` | `#private-functions-externalprivate` |
| `#initializer-functions` | `#define-initializer-functions` |
| `#aztec-validator-keys\|valkeys` | `#aztec-validator-keysvalkeys` |
| `#delayed-public-mutable` | `#delayedpublicmutable` |
| `#fee-payment-contracts-fpc` | `#use-fee-payment-contracts` |

## Test plan
- [ ] Verify anchor links resolve correctly in local dev server
- [ ] Confirm migration notes heading matches versioned copy

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: critesjosh

docs/developer_versioned_docs/version-v4.0.0-devnet.2-patch.1/docs/aztec-nr/framework-description/functions/context.md

@@ -174,7 +174,7 @@ The `args_hash` is the result of pedersen hashing all of a function's inputs.
 
 ### Return Values
 
-The return values are a set of values that are returned from an applications execution to be passed to other functions through the kernel. Developers do not need to worry about passing their function return values to the `context` directly as `Aztec.nr` takes care of it for you. See the documentation surrounding `Aztec.nr` [macro expansion](./attributes.md#after-expansion) for more details.
+The return values are a set of values that are returned from an applications execution to be passed to other functions through the kernel. Developers do not need to worry about passing their function return values to the `context` directly as `Aztec.nr` takes care of it for you. See the documentation surrounding `Aztec.nr` [macro expansion](./attributes.md#private-functions-externalprivate) for more details.
 
 ```rust
 return_values : BoundedVec\<Field, RETURN_VALUES_LENGTH\>,

docs/developer_versioned_docs/version-v4.0.0-devnet.2-patch.1/docs/aztec-nr/framework-description/functions/index.md

@@ -5,7 +5,7 @@ tags: [functions]
 description: Overview of Aztec contract functions, including private, public, and utility function types.
 ---
 
-Functions serve as the building blocks of smart contracts. Functions can be either **public**, ie they are publicly available for anyone to see and can directly interact with public state, or **private**, meaning they are executed completely client-side in the [PXE](../../../foundational-topics/pxe/index.md). Read more about how private functions work [here](./attributes.md#private-functions-private).
+Functions serve as the building blocks of smart contracts. Functions can be either **public**, ie they are publicly available for anyone to see and can directly interact with public state, or **private**, meaning they are executed completely client-side in the [PXE](../../../foundational-topics/pxe/index.md). Read more about how private functions work [here](./attributes.md#private-functions-externalprivate).
 
 Currently, any function is "mutable" in the sense that it might alter state. However, we also support static calls, similarly to EVM. A static call is essentially a call that does not alter state (it keeps state static).
 
@@ -22,7 +22,7 @@ There are also special oracle functions, which can get data from outside of the
 ## Learn more about functions
 
 - [How function visibility works in Aztec](./visibility.md)
-- How to write an [initializer function](./how_to_define_functions.md#initializer-functions)
+- How to write an [initializer function](./how_to_define_functions.md#define-initializer-functions)
 - [Oracles](../advanced/protocol_oracles.md) and how Aztec smart contracts might use them
 - [How functions work under the hood](./attributes.md)
 

docs/developer_versioned_docs/version-v4.0.0-devnet.2-patch.1/docs/cli/aztec_cli_reference.md

@@ -60,7 +60,7 @@ sidebar_position: 1
   - [aztec start](#aztec-start)
   - [aztec trigger-seed-snapshot](#aztec-trigger-seed-snapshot)
   - [aztec update](#aztec-update)
-  - [aztec validator-keys|valKeys](#aztec-validator-keys|valkeys)
+  - [aztec validator-keys|valKeys](#aztec-validator-keysvalkeys)
   - [aztec vote-on-governance-proposal](#aztec-vote-on-governance-proposal)
 ## aztec
 

docs/developer_versioned_docs/version-v4.0.0-devnet.2-patch.1/docs/foundational-topics/call_types.md

@@ -225,7 +225,7 @@ public_checks = { git = "https://github.com/AztecProtocol/aztec-packages/", tag
 
 Even with the public checks contract, achieving good privacy is hard.
 For example, if the value being checked against is unique and stored in the contract's public storage, it's then simple to find private transactions that are using that value in the enqueued public reads, and therefore link them to this contract.
-For this reason it is encouraged to try to avoid public function calls and instead privately read [Delayed Public Mutable](../aztec-nr/framework-description/state_variables.md#delayed-public-mutable) state when possible.
+For this reason it is encouraged to try to avoid public function calls and instead privately read [Delayed Public Mutable](../aztec-nr/framework-description/state_variables.md#delayedpublicmutable) state when possible.
 
 ### Public Execution
 

docs/developer_versioned_docs/version-v4.0.0-devnet.2-patch.1/docs/foundational-topics/fees.md

@@ -94,7 +94,7 @@ Fee Juice uses an enshrined `FeeJuicePortal` contract on Ethereum for bridging,
 
 An account with Fee Juice can pay for its transactions directly. A new account can even pay for its own deployment transaction, provided Fee Juice was bridged to its address before deployment.
 
-Alternatively, accounts can use [fee-paying contracts (FPCs)](../aztec-js/how_to_pay_fees.md#fee-payment-contracts-fpc) to pay for transactions. FPCs accept tokens and pay fees in Fee Juice on behalf of users. Common patterns include:
+Alternatively, accounts can use [fee-paying contracts (FPCs)](../aztec-js/how_to_pay_fees.md#use-fee-payment-contracts) to pay for transactions. FPCs accept tokens and pay fees in Fee Juice on behalf of users. Common patterns include:
 
 - **Sponsored FPCs**: Pay fees unconditionally, enabling free transactions for users
 - **Token-accepting FPCs**: Accept a specific token in exchange for paying fees

docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/aztec-nr/framework-description/functions/context.md

@@ -170,7 +170,7 @@ The `args_hash` is the result of pedersen hashing all of a function's inputs.
 
 ### Return Values
 
-The return values are a set of values that are returned from an applications execution to be passed to other functions through the kernel. Developers do not need to worry about passing their function return values to the `context` directly as `Aztec.nr` takes care of it for you. See the documentation surrounding `Aztec.nr` [macro expansion](./attributes.md#after-expansion) for more details.
+The return values are a set of values that are returned from an applications execution to be passed to other functions through the kernel. Developers do not need to worry about passing their function return values to the `context` directly as `Aztec.nr` takes care of it for you. See the documentation surrounding `Aztec.nr` [macro expansion](./attributes.md#private-functions-externalprivate) for more details.
 
 ```rust
 return_values : BoundedVec\<Field, RETURN_VALUES_LENGTH\>,

docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/aztec-nr/framework-description/functions/index.md

@@ -5,7 +5,7 @@ tags: [functions]
 description: Overview of Aztec contract functions, including private, public, and utility function types.
 ---
 
-Functions serve as the building blocks of smart contracts. Functions can be either **public**, ie they are publicly available for anyone to see and can directly interact with public state, or **private**, meaning they are executed completely client-side in the [PXE](../../../foundational-topics/pxe/index.md). Read more about how private functions work [here](./attributes.md#private-functions-private).
+Functions serve as the building blocks of smart contracts. Functions can be either **public**, ie they are publicly available for anyone to see and can directly interact with public state, or **private**, meaning they are executed completely client-side in the [PXE](../../../foundational-topics/pxe/index.md). Read more about how private functions work [here](./attributes.md#private-functions-externalprivate).
 
 Currently, any function is "mutable" in the sense that it might alter state. However, we also support static calls, similarly to EVM. A static call is essentially a call that does not alter state (it keeps state static).
 
@@ -22,7 +22,7 @@ There are also special oracle functions, which can get data from outside of the
 ## Learn more about functions
 
 - [How function visibility works in Aztec](./visibility.md)
-- How to write an [initializer function](./how_to_define_functions.md#initializer-functions)
+- How to write an [initializer function](./how_to_define_functions.md#define-initializer-functions)
 - [Oracles](../advanced/protocol_oracles.md) and how Aztec smart contracts might use them
 - [How functions work under the hood](./attributes.md)
 

docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/cli/aztec_cli_reference.md

@@ -67,7 +67,7 @@ sidebar_position: 1
   - [aztec test](#aztec-test)
   - [aztec trigger-seed-snapshot](#aztec-trigger-seed-snapshot)
   - [aztec update](#aztec-update)
-  - [aztec validator-keys|valKeys](#aztec-validator-keys|valkeys)
+  - [aztec validator-keys|valKeys](#aztec-validator-keysvalkeys)
   - [aztec vote-on-governance-proposal](#aztec-vote-on-governance-proposal)
 ## aztec
 

docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/foundational-topics/call_types.md

@@ -214,7 +214,7 @@ public_checks = { git = "https://github.com/AztecProtocol/aztec-packages/", tag
 
 Even with the public checks contract, achieving good privacy is hard.
 For example, if the value being checked against is unique and stored in the contract's public storage, it's then simple to find private transactions that are using that value in the enqueued public reads, and therefore link them to this contract.
-For this reason it is encouraged to try to avoid public function calls and instead privately read [Delayed Public Mutable](../aztec-nr/framework-description/state_variables.md#delayed-public-mutable) state when possible.
+For this reason it is encouraged to try to avoid public function calls and instead privately read [Delayed Public Mutable](../aztec-nr/framework-description/state_variables.md#delayedpublicmutable) state when possible.
 
 ### Public Execution
 

docs/developer_versioned_docs/version-v4.1.0-rc.2/docs/foundational-topics/fees.md

@@ -94,7 +94,7 @@ Fee Juice uses an enshrined `FeeJuicePortal` contract on Ethereum for bridging,
 
 An account with Fee Juice can pay for its transactions directly. A new account can even pay for its own deployment transaction, provided Fee Juice was bridged to its address before deployment.
 
-Alternatively, accounts can use [fee-paying contracts (FPCs)](../aztec-js/how_to_pay_fees.md#fee-payment-contracts-fpc) to pay for transactions. FPCs accept tokens and pay fees in Fee Juice on behalf of users. Common patterns include:
+Alternatively, accounts can use [fee-paying contracts (FPCs)](../aztec-js/how_to_pay_fees.md#use-fee-payment-contracts) to pay for transactions. FPCs accept tokens and pay fees in Fee Juice on behalf of users. Common patterns include:
 
 - **Sponsored FPCs**: Pay fees unconditionally, enabling free transactions for users
 - **Token-accepting FPCs**: Accept a specific token in exchange for paying fees