patch 9.0.1661: BUCK files are not recognized

Problem:    BUCK files are not recognized.
Solution:   Recognize BUCK files as "bzl". (Son Luong Ngoc, closes #12564)

runtime/filetype.vim

@@ -266,11 +266,11 @@ au BufNewFile,BufRead */etc/blkid.tab,*/etc/blkid.tab.old   setf xml
 " BSDL
 au BufNewFile,BufRead *.bsd,*.bsdl			setf bsdl
 
-" Bazel (http://bazel.io)
+" Bazel (https://bazel.build) and Buck2 (https://buck2.build/)
 autocmd BufRead,BufNewFile *.bzl,*.bazel,WORKSPACE,WORKSPACE.bzlmod	setf bzl
 if has("fname_case")
-  " There is another check for BUILD further below.
-  autocmd BufRead,BufNewFile *.BUILD,BUILD		setf bzl
+  " There is another check for BUILD and BUCK further below.
+  autocmd BufRead,BufNewFile *.BUILD,BUILD,BUCK		setf bzl
 endif
 
 " Busted (Lua unit testing framework - configuration files)
@@ -2605,9 +2605,9 @@ au BufNewFile,BufRead *asterisk*/*voicemail.conf* call s:StarSetf('asteriskvm')
 " Bazaar version control
 au BufNewFile,BufRead bzr_log.*			setf bzr
 
-" Bazel build file
+" Bazel and Buck2 build file
 if !has("fname_case")
-  au BufNewFile,BufRead *.BUILD,BUILD		setf bzl
+  au BufNewFile,BufRead *.BUILD,BUILD,BUCK	setf bzl
 endif
 
 " BIND zone

src/testdir/test_filetype.vim

@@ -814,7 +814,7 @@ enddef
 def s:GetFilenameCaseChecks(): dict<list<string>>
   return {
     modula2: ['file.DEF'],
-    bzl: ['file.BUILD', 'BUILD'],
+    bzl: ['file.BUILD', 'BUILD', 'BUCK'],
   }
 enddef
 

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1661,
 /**/
     1660,
 /**/