[vim] Detect git-cl description files as gitcommit files.

tools/vim/filetypes.vim

Index: tools/vim/filetypes.vim
diff --git a/tools/vim/filetypes.vim b/tools/vim/filetypes.vim
index 3e7c8f9eada3264b1e8dde4da57e46c8bb131a34..8e0ed98ae5aa770629be428ad062b84f045027d1 100644
--- a/tools/vim/filetypes.vim
+++ b/tools/vim/filetypes.vim
@@ -1,9 +1,10 @@
-" To get syntax highlighting and tab settings for gyp(i) and DEPS files,
-" add the following to your .vimrc file:
+" To get syntax highlighting and tab settings for gyp(i), DEPS, and 'git cl'
+" changelist description files, add the following to your .vimrc file:
 "     so /path/to/src/tools/vim/filetypes.vim
-
+"
 augroup filetype
         au! BufRead,BufNewFile *.gyp    set filetype=python expandtab tabstop=2 shiftwidth=2
         au! BufRead,BufNewFile *.gypi   set filetype=python expandtab tabstop=2 shiftwidth=2
         au! BufRead,BufNewFile DEPS     set filetype=python expandtab tabstop=2 shiftwidth=2
+        au! BufRead,BufNewFile cl_description* set filetype=gitcommit
 augroup END