title: Mypy does not ignore mpi4py module with syntax error
body: <p>In mypy.ini there is</p>
  <pre><code>[mypy-mpi4py]
  ignore_missing_imports = True
  </code></pre>
  <p>With this mypy is getting the following error</p>
  <pre><code>Success: no issues found in 4 source files
  s\d\L\.env\lib\site-packages\mpi4py\MPI.pyi:948: error:
  invalid syntax  [syntax]
          def __new__(cls, buf: Buffer, /) -&gt; memory: ...
                                         ^
  Found 1 error in 1 file (errors prevented further checking)
  Success: no issues found in 3 source files
  </code></pre>
  <p>How can I setup the config to ignore the module ?</p>