vim-patch:9.0.1176: smithy files are not recognized (#21751)

Problem:    smithy files are not recognized.
Solution:   Add a pattern for Smithy files. (Chris Kipp, closes vim/vim#11804)

f68cddabff

Co-authored-by: Chris Kipp <ckipp@pm.me>

src/nvim/testdir/test_filetype.vim

@@ -529,6 +529,7 @@ let s:filename_checks = {
     \ 'smarty': ['file.tpl'],
     \ 'smcl': ['file.hlp', 'file.ihlp', 'file.smcl'],
     \ 'smith': ['file.smt', 'file.smith'],
+    \ 'smithy': ['file.smithy'],
     \ 'sml': ['file.sml'],
     \ 'snobol4': ['file.sno', 'file.spt'],
     \ 'solidity': ['file.sol'],