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/pi_netrw.txt b/runtime/doc/pi_netrw.txt
index 2b7e565..709b847 100644
--- a/runtime/doc/pi_netrw.txt
+++ b/runtime/doc/pi_netrw.txt
@@ -1,4 +1,4 @@
-*pi_netrw.txt*  For Vim version 8.1.  Last change: 2017 Nov 03
+*pi_netrw.txt*  For Vim version 8.1.  Last change: 2019 May 05
 
 	    ------------------------------------------------
 	    NETRW REFERENCE MANUAL    by Charles E. Campbell
@@ -114,8 +114,6 @@
 13. Todo..................................................|netrw-todo|
 14. Credits...............................................|netrw-credits|
 
-{Vi does not have any of this}
-
 ==============================================================================
 2. Starting With Netrw					*netrw-start* {{{1