Update runtime files. Convert a couple of help files to utf-8.
diff --git a/runtime/doc/usr_24.txt b/runtime/doc/usr_24.txt
index 22b6c8b..daf291d 100644
--- a/runtime/doc/usr_24.txt
+++ b/runtime/doc/usr_24.txt
@@ -1,4 +1,4 @@
-*usr_24.txt*	For Vim version 8.0.  Last change: 2006 Jul 23
+*usr_24.txt*	For Vim version 8.0.  Last change: 2018 Mar 18
 
 		     VIM USER MANUAL - by Bram Moolenaar
 
@@ -538,8 +538,8 @@
 *24.9*	Digraphs
 
 Some characters are not on the keyboard.  For example, the copyright character
-(©).  To type these characters in Vim, you use digraphs, where two characters
-represent one.  To enter a ©, for example, you press three keys: >
+(©).  To type these characters in Vim, you use digraphs, where two characters
+represent one.  To enter a ©, for example, you press three keys: >
 
 	CTRL-K Co
 
@@ -549,12 +549,12 @@
 
 Vim will display the digraph table.  Here are three lines of it:
 
-  AC ~_ 159  NS |  160  !I ¡  161  Ct ¢  162  Pd £  163  Cu ¤  164  Ye ¥  165 ~
-  BB ¦  166  SE §  167  ': ¨  168  Co ©  169  -a ª  170  << «  171  NO ¬  172 ~
-  -- ­  173  Rg ®  174  'm ¯  175  DG °  176  +- ±  177  2S ²  178  3S ³  179 ~
+  AC ~_ 159  NS |  160  !I ¡  161  Ct ¢  162  Pd £  163  Cu ¤  164  Ye ¥  165 ~
+  BB ¦  166  SE §  167  ': ¨  168  Co ©  169  -a ª  170  << «  171  NO ¬  172 ~
+  -- ­  173  Rg ®  174  'm ¯  175  DG °  176  +- ±  177  2S ²  178  3S ³  179 ~
 
 This shows, for example, that the digraph you get by typing CTRL-K Pd is the
-character (£).  This is character number 163 (decimal).
+character (£).  This is character number 163 (decimal).
    Pd is short for Pound.  Most digraphs are selected to give you a hint about
 the character they will produce.  If you look through the list you will
 understand the logic.
@@ -569,9 +569,9 @@
 
 You can define your own digraphs.  Example: >
 
-	:digraph a" ä
+	:digraph a" ä
 
-This defines that CTRL-K a" inserts an ä character.  You can also specify the
+This defines that CTRL-K a" inserts an ä character.  You can also specify the
 character with a decimal number.  This defines the same digraph: >
 
 	:digraph a" 228