vim-patch:9.0.1415: Crystal files are not recognized

Problem:    Crystal files are not recognized.
Solution:   Add a pattern for Crystal files. (Amaan Qureshi, closes vim/vim#12175)

7c4516fe93

Co-authored-by: Amaan Qureshi <amaanq12@gmail.com>

test/old/testdir/test_filetype.vim

@@ -133,6 +133,7 @@ let s:filename_checks = {
     \ 'cqlang': ['file.cql'],
     \ 'crm': ['file.crm'],
     \ 'crontab': ['crontab', 'crontab.file', '/etc/cron.d/file', 'any/etc/cron.d/file'],
+    \ 'crystal': ['file.cr'],
     \ 'cs': ['file.cs', 'file.csx'],
     \ 'csc': ['file.csc'],
     \ 'csdl': ['file.csdl'],