feat: add lint for no negated request_cookies

[fzipi]

what

• detects when SecRule directives use negated !REQUEST_COOKIES targets
• yields clear error messages instructing users to use SecRuleUpdateTargetById instead
• handles edge cases like multiple negated cookies, chained rules, and case-insensitive matching
• only reports once per rule even if multiple negated REQUEST_COOKIES targets exist
• update documentation

why

• prevent adding new rules with old pattern

refs

• Fixes Add new linting rule for preventing SecRule directives to remove targets from REQUEST_COOKIES #112

[Copilot]

Pull request overview

This PR adds a new linting rule to detect and prevent the use of negated !REQUEST_COOKIES targets in SecRule directives, enforcing a policy change that cookie exclusions should be implemented using SecRuleUpdateTargetById directives in separate post-CRS configuration files instead.

Changes:

• Implements a new NoNegatedRequestCookies rule that detects negated REQUEST_COOKIES patterns in SecRule directives
• Adds comprehensive test coverage with 195 lines of tests covering various edge cases
• Enhances the documentation generator with code block formatting functionality for better rendering of ModSecurity examples

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/crs_linter/rules/no_negated_request_cookies.py	New linting rule that checks for !REQUEST_COOKIES targets and yields clear error messages directing users to use SecRuleUpdateTargetById
tests/test_no_negated_request_cookies.py	Comprehensive test suite covering valid/invalid patterns, case sensitivity, chained rules, and multiple negated cookies
src/crs_linter/linter.py	Imports the new rule module to enable auto-registration
generate_rules_docs.py	Adds format_code_blocks() function to properly format ModSecurity code examples in docstrings with markdown triple backticks
README.md	Auto-generated documentation updates including the new rule description and improved code block formatting for all examples

[airween]

Looks good to me. Probably we can merge after a new CRS release (current released version does not fit the expected rules).

[fzipi]

Moved the enhanced documentation generator to #115, as it has nothing to do with the intended changes here.