vim-patch:9.1.0424: filetype: slint files are not recognized

Problem:  filetype: slint files are not recognized
Solution: Detect '*.slint' files as slint filetype,
          include basic sling filetype plugin
          (Riley Bruins)

closes: vim/vim#14808

aa3104b07a

Co-authored-by: Riley Bruins <ribru17@hotmail.com>

runtime/lua/vim/filetype.lua

@@ -970,6 +970,7 @@ local extension = {
   cdf = 'skill',
   sl = 'slang',
   ice = 'slice',
+  slint = 'slint',
   score = 'slrnsc',
   sol = 'solidity',
   smali = 'smali',