vim-patch:9.1.2100: filetype: tiltfiles are not recognized (#37477)

Problem:  filetype: tiltfiles are not recognized
Solution: Detect Tiltfiles.* and *.tiltfiles as tiltfile  filetype.
          (Luis Davim)

Reference:
- https://docs.tilt.dev/api.html

fixes:  vim/vim#19214
closes: vim/vim#19218

ff0e5d994c

Co-authored-by: Luis Davim <luis.davim@gmail.com>

test/old/testdir/test_filetype.vim

@@ -885,6 +885,7 @@ func s:GetFilenameChecks() abort
     \ 'tidy': ['.tidyrc', 'tidyrc', 'tidy.conf'],
     \ 'tiger': ['file.tig'],
     \ 'tilde': ['file.t.html'],
+    \ 'tiltfile': ['Tiltfile', 'tiltfile', 'file.Tiltfile', 'file.tiltfile', 'Tiltfile.debian'],
     \ 'tla': ['file.tla'],
     \ 'tli': ['file.tli'],
     \ 'tmux': ['tmuxfile.conf', '.tmuxfile.conf', '.tmux-file.conf', '.tmux.conf', 'tmux-file.conf', 'tmux.conf', 'tmux.conf.local'],