Extend documentation for redefined-builtin

[zenlyj]

Closes #10160

Type of Changes

	Type
	🐛 Bug fix
	✨ New feature
	🔨 Refactoring
✓	📜 Docs

Description

The redefined-builtin check has an option - allowed-redefined-builtins that allows users to specify names that are allowed to shadow built-ins. However, there are exceptions where this option does not apply, which might lead to confusion. Users may reasonably expect the option to be effective in all cases.

The option is not effective when:

• the shadowing occurs at module level
• the shadowing occurs at local scope, but the global keyword is applied to the name

The justification for these exceptions was discussed in #3643. Therefore, these cases should be documented to provide better clarity for users.

Additionally, add functional test for the global keyword case, as it is not covered by existing tests.

Screenshot reference of updated doc page:

Closes #10160

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.80%. Comparing base (0d5439b) to head (934539c).
Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   95.80%   95.80%           
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  Files         174      174           
  Lines       18976    18976           
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  Hits        18180    18180           
  Misses        796      796           

[DanielNoord]

Thanks! One comment about the link, the rest LGTM!