gitedit.py: Use canonical git commit template
gitedit.py: Use canonical git commit template

Update the template message to match that of "git commit",
including prefixing each line of "git status" with a comment
character.

Use os.linesep rather than assuming "\n".

Signed-off-by: Darren Hart (VMware) <38f9eaa30910c40b06f5a60020b1222f2a953801@infradead.org>

dvhart/gedit-git-plugin