patch 8.1.1280: remarks about functionality not in Vi clutters the help

Problem:    Remarks about functionality not in Vi clutters the help.
Solution:   Move all info about what is new in Vim or already existed in Vi to
            vi_diff.txt.  Remove {not in Vi} remarks. (closes #4268) Add
            "noet" to the help files modeline.  Also include many other help
            file improvements.
diff --git a/runtime/doc/arabic.txt b/runtime/doc/arabic.txt
index 2303a2b..b3b61a1 100644
--- a/runtime/doc/arabic.txt
+++ b/runtime/doc/arabic.txt
@@ -1,4 +1,4 @@
-*arabic.txt*	For Vim version 8.1.  Last change: 2010 Nov 13
+*arabic.txt*	For Vim version 8.1.  Last change: 2019 May 05
 
 
 		  VIM REFERENCE MANUAL	  by Nadim Shaikli
@@ -6,7 +6,6 @@
 
 Arabic Language support (options & mappings) for Vim		*Arabic*
 
-{Vi does not have any of these commands}
 
 								*E800*
 In order to use right-to-left and Arabic mapping support, it is