Modified WillInsertText() so that it adds a mozbr if
the last char in the plaintext string is a newline,
and we are inserting at the end of the doc. This gives
the blank line people expect to see.
r=jfrancis@netscape.comsr=sfraser@netscape.com
git-svn-id: svn://10.0.0.236/trunk@106363 18797224-902f-48f8-a5cc-f745e15eee43