vim-patch:9.0.0604: luacheckrc file is not recognized (#20371)

Problem:    Luacheckrc file is not recognized.
Solution:   Use lua filetype for luacheckrc. (closes vim/vim#11236)
49c311c9b1

runtime/filetype.vim

@@ -1113,6 +1113,9 @@ au BufNewFile,BufRead *.lou,*.lout		setf lout
 " Lua
 au BufNewFile,BufRead *.lua			setf lua
 
+" Luacheck
+au BufNewFile,BufRead .luacheckrc		setf lua
+
 " Luarocks
 au BufNewFile,BufRead *.rockspec		setf lua
 

runtime/lua/vim/filetype.lua

@@ -1455,6 +1455,7 @@ local filename = {
   ['.sawfishrc'] = 'lisp',
   ['/etc/login.access'] = 'loginaccess',
   ['/etc/login.defs'] = 'logindefs',
+  ['.luacheckrc'] = 'lua',
   ['lynx.cfg'] = 'lynx',
   ['m3overrides'] = 'm3build',
   ['m3makefile'] = 'm3build',

src/nvim/testdir/test_filetype.vim

@@ -328,7 +328,7 @@ let s:filename_checks = {
     \ 'lpc': ['file.lpc', 'file.ulpc'],
     \ 'lsl': ['file.lsl'],
     \ 'lss': ['file.lss'],
-    \ 'lua': ['file.lua', 'file.rockspec', 'file.nse'],
+    \ 'lua': ['file.lua', 'file.rockspec', 'file.nse', '.luacheckrc'],
     \ 'lynx': ['lynx.cfg'],
     \ 'lyrics': ['file.lrc'],
     \ 'm3build': ['m3makefile', 'm3overrides'],