wt-status code is used to provide a reminder of changes included and
not included for the commit message template opened in the operator's
text editor by "git commit".  Therefore each line of its output begins
with the comment character "#":

	# Please enter the commit message for your changes. Lines starting

Use the new status_printf{,_ln,_more} functions to take care of adding
"#" to the beginning of such status lines automatically.  Using these
will have two advantages over the current code:

 - The obvious one is to force separation of the "#" from the
   translatable part of the message when git learns to translate its
   output.

 - Another advantage is that this makes it easier for us to drop "#"
   prefix in "git status" output in later versions of git if we want
   to.
Explained-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NJonathan Nieder <jrnieder@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>