commands: wrap docstrings at 70 characters
It is no longer necessary to wrap the docstrings at 70 characters in
the source -- with the reST parser, they are re-formatted to fit the
terminal when shown.
However, wrapping the docstrings at 78 characters makes life harder
for translators because it marks a lot of strings as fuzzy for no good
reason. When un-marking them, the translators would have to examine
each string again and determine if it is merely re-wrapped or if the
content was also changed.
The long lines also introduce very ugly linebreaks in the .po files if
they are processed using the standard Gettext tools without using
something like '--width 85' all the time.