Runtime files update.

runtime/doc/message.txt

@@ -1,4 +1,4 @@
-*message.txt*   For Vim version 8.1.  Last change: 2019 May 18
+*message.txt*   For Vim version 8.1.  Last change: 2019 Aug 23
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -479,6 +479,9 @@ out-of-memory situation.  First make sure that any changes are saved.  Then
 try to solve the memory shortage.  To stay on the safe side, exit Vim and
 start again.
 
+If this happens while Vim is still initializing, editing files is very
+unlikely to work, therefore Vim will exit with value 123. 
+
 Buffers are only partly kept in memory, thus editing a very large file is
 unlikely to cause an out-of-memory situation.  Undo information is completely
 in memory, you can reduce that with these options:
@@ -809,6 +812,8 @@ To reduce the number of hit-enter prompts:
 - Set 'cmdheight' to 2 or higher.
 - Add flags to 'shortmess'.
 - Reset 'showcmd' and/or 'ruler'.
+- Make sure `:echo` text is shorter than or equal to |v:echospace| screen
+  cells.
 
 If your script causes the hit-enter prompt and you don't know why, you may
 find the |v:scrollstart| variable useful.