runtime(doc): Update the version9.txt with a template for version 9.1 enhancements (#13165)

Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/version9.txt

@@ -31679,4 +31679,85 @@ Solution:   make menu generation script use Vim9 script, fix errors.
 Files:      runtime/makemenu.vim
 
 
+==============================================================================
+VERSION 9.1				*version-9.1* *version9.1* *vim-9.1*
+
+This section is about improvements made between version 9.0 and 9.1.
+
+This release has hundreds of bug fixes, there are a few new features and there
+are many minor improvements.
+
+Vim9 classes
+------------
+
+Virtual text
+------------
+
+Smooth Scroll
+-------------
+
+Other improvements				*new-other-9.1*
+------------------
+
+Changed						*changed-9.1*
+-------
+
+Added						*added-9.1*
+-----
+
+Various syntax, indent and other plugins were added.
+
+Functions: ~
+
+|err_teapot()|		produce error 418 or 503
+|getbufoneline()|	get a one line from the specified buffer
+|getcellwidths()|	get character cell width overrides
+|getmouseshape()|	get name of the current mouse shape
+|getscriptinfo()|	get list of sourced vim scripts
+|indexof()|		index in a List or Blob of a true expression
+|instanceof()|		check if a variable is an instance of a given class
+|keytrans()|		translate internal key codes to be usable with |:map|
+|popup_findecho()|	get window ID for popup used for |:echowindow|
+|setcmdline()|		set the current command line
+|strutf16len()|		number of UTF-16 code units in a string
+|swapfilelist()|	list of existing swap files in 'directory'
+|test_mswin_event()|	generate an MS-Windows event for testing
+|utf16idx()|		UTF-16 index of a byte in a string
+
+
+Autocommands: ~
+
+|TextChangedT|		after a change was made to the text in Terminal mode
+|WinResized|		after a window in the current tab page is resized
+
+
+Commands: ~
+
+|:abstract|		define an Vim9 abstract class
+|:class|		start of a class specification
+|:defer|		call function when current function is done
+|:echowindow|		same as :echomsg, but use a popup window
+|:endinterface|		end of an interface specification
+|:endclass|		end of a class specification
+|:horizontal|		following window command work horizontally
+|:interface|		start of an interface specification
+|:public|		prefix for a class or object member
+|:static|		prefix for a class member or function
+|:this|			prefix for an object member
+
+
+Options: ~
+
+'jumpoptions'		specifies how jumping is done
+'keyprotocol'		what keyboard protocol to use for what terminal
+'lispoptions'		changes how Lisp indenting is done
+'showcmdloc'		where to show (partial) command
+'smoothscroll'		scroll by screen lines when 'wrap' is set
+'splitkeep'		determines scroll behavior for split windows
+
+
+Patches						*patches-9.1*
+-------
+
+
  vim:tw=78:ts=8:noet:ft=help:norl: