Document file_finders in more detail
Document file_finders in more detail

* The `sdist` command is affected by its existance
* Correction: MANIFEST.in can still be used (in principle) to include files too.

pypa/setuptools_scm,RonnyPfannschmidt/setuptools_scm,pypa/setuptools_scm,RonnyPfannschmidt/setuptools_scm