Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index b73a39c..88fda8e 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 8.0.  Last change: 2018 Apr 30
+*syntax.txt*	For Vim version 8.1.  Last change: 2018 Apr 30
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar