vim-patch:9.2.0333: filetype: PklProject files are not recognized (#38949)

Problem:  filetype: PklProject files are not recognized
Solution: Detect PklProject files as pkl filetype
          (Nihaal Sangha).

Reference:
https://pkl-lang.org/
https://github.com/apple/pkl
https://github.com/apple/pkl-pantry

closes: vim/vim#19948

871e6c6cf9

Co-authored-by: Nihaal Sangha <nihaal.git@gmail.com>

runtime/lua/vim/filetype.lua

@@ -1874,6 +1874,7 @@ local filename = {
   pinercex = 'pine',
   ['/etc/pinforc'] = 'pinfo',
   ['/.pinforc'] = 'pinfo',
+  PklProject = 'pkl',
   ['.povrayrc'] = 'povini',
   printcap = function(_path, _bufnr)
     return 'ptcap', function(b)