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/debugger.txt b/runtime/doc/debugger.txt
index 3370cf0..cbf2009 100644
--- a/runtime/doc/debugger.txt
+++ b/runtime/doc/debugger.txt
@@ -1,4 +1,4 @@
-*debugger.txt*  For Vim version 8.1.  Last change: 2017 Nov 21
+*debugger.txt*  For Vim version 8.1.  Last change: 2019 May 05
 
 
 		  VIM REFERENCE MANUAL    by Gordon Prieur
@@ -10,7 +10,6 @@
 2. Vim Compile Options		|debugger-compilation|
 3. Integrated Debuggers		|debugger-integration|
 
-{Vi does not have any of these features}
 
 ==============================================================================
 1. Debugger Features					*debugger-features*