Update code review guidelines in SKILL.md (#15172)

* Update code review guidelines in SKILL.md

Clarify criteria for code review and coding style.

* updating DIRECTORY.md

* Fix formatting issues in SKILL.md

---------

Co-authored-by: cclauss <cclauss@users.noreply.github.com>

Author: cclauss

.github/skills/code-review/SKILL.md

@@ -2,7 +2,7 @@
 
 Review a pull request against the rules already written in
 [`CONTRIBUTING.md`](../../../CONTRIBUTING.md). The goal is a review that any
-reviewer (human or AI) can run the same way every time and that produces a clear,
+reviewer (human or AI) can run the same way every time, and that produces a clear,
 kind, actionable verdict.
 
 ## How to run this skill
@@ -16,13 +16,16 @@ suggest the fix — never just "rejected".
 - [ ] The change adds, fixes, or documents **one algorithm** — not multiple, and
       not both code and doctest changes in the same PR.
 - [ ] It is a genuine algorithm or data structure (see the *What is an Algorithm?*
-      section), not a script, snippet, or exercise dump.
+      section), not a script, snippet, how-to-use for an existing API, or exercise
+      dump.
 - [ ] It is **not already in the repository** (search the existing directories).
 - [ ] **No earlier open PR** already does the same thing — link it if one exists.
 - [ ] Properly attributed — no plagiarism; prior sources credited.
 
 ### 2. Coding Style
 
+- [ ] `from __future__ import annotations` is not needed because this repo only uses
+      the latest version of CPython.
 - [ ] File and directory names are lowercase, use underscores, and land inside an
       existing directory.
 - [ ] Public functions/classes have **type hints**.

DIRECTORY.md

@@ -462,6 +462,7 @@
 
 ## Fuzzy Logic
   * [Fuzzy Operations](fuzzy_logic/fuzzy_operations.py)
+  * [Fuzzy Set Operations](fuzzy_logic/fuzzy_set_operations.py)
 
 ## Genetic Algorithm
   * [Basic String](genetic_algorithm/basic_string.py)