runtime(filetype): detect *.ck files as Chuck filetype (#13888)

closes #13886

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index 0c2869a..f1e1a76 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -317,6 +317,9 @@
 " Chatito
 au BufNewFile,BufRead *.chatito			setf chatito
 
+" Chuck
+au BufNewFile,BufRead *.ck			setf chuck
+
 " Comshare Dimension Definition Language
 au BufNewFile,BufRead *.cdl			setf cdl