vim-patch:9.0.1263: KDL files are not recognized (#22058)

Problem:    KDL files are not recognized.
Solution:   Add a pattern for KDL files. (Amaan Qureshi, closes vim/vim#11898)

907349a743

Co-authored-by: Amaan Qureshi <amaanq12@gmail.com>

runtime/lua/vim/filetype.lua

@@ -569,6 +569,7 @@ local extension = {
   libsonnet = 'jsonnet',
   jsp = 'jsp',
   jl = 'julia',
+  kdl = 'kdl',
   kv = 'kivy',
   kix = 'kix',
   kts = 'kotlin',