Add Github test that no "added" line contains end-of-line whitespace

[samsrabin]

End-of-line whitespace is something we've agreed is "evil." Lots of FORTRAN formatting is hard to automate, but this is easy enough.

This would apply to all files except Python files, since black takes care of this for those.

[ekluzek]

This is something that can come out of #1768 with a pre-commit workflow.