[clang-tidy] detect `errno` being compared with a number literal

The actual values of the error constants utilized by `errno` are not being document so technically that makes them implementation-defined (it is stated more than specified by the standard might be defined). So checking it against a number might not be portable.

See
https://en.cppreference.com/w/c/error/errno_macros.html
https://en.cppreference.com/w/cpp/error/errno_macros.html
https://www.man7.org/linux/man-pages/man3/errno.3.html

They are actually document as "implementation-defined" in https://en.cppreference.com/w/c/header/errno.html.

And the Visual Studio documentation provides some actual values: https://learn.microsoft.com/en-us/cpp/c-runtime-library/errno-constants.

Start at the clang-tidy entry point and locate the existing checks related to errno or portability diagnostics. Confirm how comparisons with numeric literals are represented and tested, then define the diagnostic behavior for detecting errno compared with a number literal. Done means the new case is diagnosed with coverage for the relevant comparison forms.

Written by the indexing model from the issue text.