fix typeshed files sometimes being treated as source files which can lead to renames causing edits to be applied to typeshed files

[DetachHead]

fixes #927

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

spack (https://github.com/spack/spack)
-   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/mpich/package.py:65:5 - warning: Result of call expression is of type "(pkg: type[PackageBase]) -> None" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
+   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/mpich/package.py:65:5 - warning: Result of call expression is of type "((pkg: type[PackageBase]) -> None)" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
-   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/mpich/package.py:67:5 - warning: Result of call expression is of type "(pkg: type[PackageBase]) -> None" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
+   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/mpich/package.py:67:5 - warning: Result of call expression is of type "((pkg: type[PackageBase]) -> None)" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
-   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/netlib-lapack/package.py:59:5 - warning: Result of call expression is of type "(pkg: type[PackageBase]) -> None" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
+   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/netlib-lapack/package.py:59:5 - warning: Result of call expression is of type "((pkg: type[PackageBase]) -> None)" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
-   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/netlib-lapack/package.py:60:5 - warning: Result of call expression is of type "(pkg: type[PackageBase]) -> None" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
+   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/netlib-lapack/package.py:60:5 - warning: Result of call expression is of type "((pkg: type[PackageBase]) -> None)" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
-   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/netlib-lapack/package.py:61:5 - warning: Result of call expression is of type "(pkg: type[PackageBase]) -> None" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)
+   /tmp/mypy_primer/projects/spack/var/spack/repos/tutorial/packages/netlib-lapack/package.py:61:5 - warning: Result of call expression is of type "((pkg: type[PackageBase]) -> None)" and is not used; assign to variable "_" if this is intentional (reportUnusedCallResult)