vim-patch:9.0.1412: Pony files are not recognized (#22721)

Problem:    Pony files are not recognized.
Solution:   Add a pattern for Pony files. (Amaan Qureshi, closes vim/vim#12155)

6e377eca8d

runtime/lua/vim/filetype.lua

@@ -800,6 +800,7 @@ local extension = {
   pod = 'pod',
   filter = 'poefilter',
   pk = 'poke',
+  pony = 'pony',
   ps = 'postscr',
   epsi = 'postscr',
   afm = 'postscr',