vim-patch:9.1.1694: filetype: Buck eXtension Lang files are not recognized (#35504)

Problem:  filetype: Buck eXtension Lang files are not recognized
Solution: Detect *.bxl files as bzl filetype.
          (Jade Lovelace)

References:
- https://buck2.build/docs/bxl/

closes: vim/vim#18130

3aea867b27

Co-authored-by: Jade Lovelace <jadel@mercury.com>

runtime/lua/vim/filetype.lua

@@ -268,6 +268,7 @@ local extension = {
       or 'btm'
   end,
   bzl = 'bzl',
+  bxl = 'bzl',
   bazel = 'bzl',
   BUILD = 'bzl',
   mdh = 'c',