[BUG] Shared utility module fails in coverage analysis #7872

Describe the bug

When enabling coverage analysis in a package compiled with the shared utility module, coverage.py complains that it cannot find the module source:

  File "/opt/hostedtoolcache/Python/3.12.13/x64/lib/python3.12/site-packages/coverage/python.py", line 67, in get_python_source
    raise NoSource(f"No source for code: '{filename}'.", slug="no-source")
coverage.exceptions.NoSource: No source for code: '/home/runner/work/cython/cython/Cython/_shared.pyx'.

Code to reproduce the behaviour:

No response

Expected behaviour

In general, it is unlikely that users care about the shared utility module when it comes to coverage analysis.

Possible ideas:

• The shared module could be ignored in general, but it might be difficult to detect.
• All modules for which the source code cannot be found could be marked as excluded, but that might also impact user modules.
• Require users to exclude the module themselves in their coverage config.

OS

No response

Python version

No response

Cython version

master

Additional context

No response