Add notes to ImportError for common issues

[FFY00]

Feature or enhancement

Proposal:

ImportErrors are very common, and almost always dependent on the interpreter initialization and/or environment setup. There are many common issues we could try to detect, and give users hints on the possible cause.

• Failing to load native modules when a module for a different ABI is available
  • Eg. Py_GIL_DISABLED is not set on Windows #127294 (comment)
    • A .cp313t-win_amd64.pyd module is available, but we were looking for .cp313-win_amd64.pyd
• Failing to import a non-stdlib module with the site initialization disabled (-S)
• Failing to import a module available in the user site-packages with the user site initialization disabled (-s)
• Failing to import a module available in . with PYTHONSAFEPATH/-P enabled
• Failing to import a module when ignoring PYTHON* environment variables (-E) but PYTHONPATH or PYTHONHOME are set (which users might be relying on)
• (suggest more!)

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

[ZeroIntensity]

Failing to import a module when ignore PYTHON* environment variables (-E) but PYTHONPATH or PYTHONHOME are set (which users might be relying on)

Related: #125873