vim-patch:9.1.0366: filetype: ondir files are not recognized

Problem:  filetype: ondir files are not recognized
Solution: Detect '.ondirrc' as ondir filetype
          (Jon Parise)

closes: vim/vim#14604

ea999037a4

Co-authored-by: Jon Parise <jon@indelible.org>

test/old/testdir/test_filetype.vim

@@ -519,6 +519,7 @@ func s:GetFilenameChecks() abort
     \ 'octave': ['octaverc', '.octaverc', 'octave.conf', 'any/.local/share/octave/history'],
     \ 'odin': ['file.odin'],
     \ 'omnimark': ['file.xom', 'file.xin'],
+    \ 'ondir': ['.ondirrc'],
     \ 'opam': ['opam', 'file.opam', 'file.opam.template'],
     \ 'openroad': ['file.or'],
     \ 'openscad': ['file.scad'],