vim-patch:9.0.0692: PoE filter files are not recognized (#20542)

Problem:    PoE filter files are not recognized.
Solution:   Add a pattern to detect PoE filter files. (closes vim/vim#11305)
b7f52f5659

src/nvim/testdir/test_filetype.vim

@@ -427,6 +427,7 @@ let s:filename_checks = {
     \ 'plsql': ['file.pls', 'file.plsql'],
     \ 'po': ['file.po', 'file.pot'],
     \ 'pod': ['file.pod'],
+    \ 'poefilter': ['file.filter'],
     \ 'poke': ['file.pk'],
     \ 'postscr': ['file.ps', 'file.pfa', 'file.afm', 'file.eps', 'file.epsf', 'file.epsi', 'file.ai'],
     \ 'pov': ['file.pov'],