add hints to description of action=edit

add hints to description of action=edit

add a hint to appendtext about section=new. I have seen, that people
build up the new header by itself and concat that with the section text.
It is easy to use section=new.

Feel free to change my english, if you think, that is not good worded.

Change-Id: I0642d496441c8fd375e8cb5dc383124b9ac25235