Update runtime files.
diff --git a/runtime/doc/digraph.txt b/runtime/doc/digraph.txt
index 3b6424a..600692e 100644
--- a/runtime/doc/digraph.txt
+++ b/runtime/doc/digraph.txt
@@ -1,4 +1,4 @@
-*digraph.txt*   For Vim version 8.1.  Last change: 2016 Nov 04
+*digraph.txt*   For Vim version 8.1.  Last change: 2018 Dec 14
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar