Make ftdetect play nice with vanilla VIM

Per `:help ftdetect`, VIM wraps these in an augroup anyway. Neovim is
okay with nesting groups, but vanilla VIM doesn't play along so happily.

Author: alerque

ftdetect/tridactyl.vim

@@ -1,8 +1,3 @@
-augroup VimTridactyl
-	autocmd!
-augroup END
-
-autocmd VimTridactyl BufNewFile,BufRead *tridactylrc setf tridactyl
-autocmd VimTridactyl FileType tridactyl setlocal commentstring=\"\ %s
-
-" vim: set noet ts=4 sw=4 sts=4:
+" vint: -ProhibitAutocmdWithNoGroup
+autocmd BufNewFile,BufRead *tridactylrc setf tridactyl
+autocmd FileType tridactyl setlocal commentstring=\"\ %s