Fix more 'cpo' issues in runtime files.
diff --git a/runtime/doc/diff.txt b/runtime/doc/diff.txt
index bf40afa..ab582dc 100644
--- a/runtime/doc/diff.txt
+++ b/runtime/doc/diff.txt
@@ -1,4 +1,4 @@
-*diff.txt*      For Vim version 7.3.  Last change: 2011 Apr 14
+*diff.txt*      For Vim version 7.3.  Last change: 2012 May 18
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar