clone: reorder --recursive/--recurse-submodules

clone: reorder --recursive/--recurse-submodules

The previous step made an option that is an alias to another option
identify itself as an alias to the latter.  Because it is easier to
scan the list when a pointer goes backward to what a reader already
has seen, mention "recurse-submodules" first with its true short
help string, and then "recurse" with the statement that it is a
synonym to "recurse-submodules".

Signed-off-by: Junio C Hamano <gitster@pobox.com>