Update runtime files. Convert a couple of help files to utf-8.
diff --git a/runtime/doc/pattern.txt b/runtime/doc/pattern.txt
index a4d0d2e..ead319c 100644
--- a/runtime/doc/pattern.txt
+++ b/runtime/doc/pattern.txt
@@ -1,4 +1,4 @@
-*pattern.txt*   For Vim version 8.0.  Last change: 2018 Feb 04
+*pattern.txt*   For Vim version 8.0.  Last change: 2018 Mar 13
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -1166,7 +1166,8 @@
 	- Matching with a collection can be slow, because each character in
 	  the text has to be compared with each character in the collection.
 	  Use one of the other atoms above when possible.  Example: "\d" is
-	  much faster than "[0-9]" and matches the same characters.
+	  much faster than "[0-9]" and matches the same characters.  However,
+	  the new |NFA| regexp engine deals with this better than the old one.
 
 						*/\%[]* *E69* *E70* *E369*
 \%[]	A sequence of optionally matched atoms.  This always matches.