help: convert git_cmd to page in one place
Depending on the chosen format of help pages, git-help uses function
show_man_page, show_info_page, or show_html_page. The first thing all
three functions do is to convert given `git_cmd` to a `page` using
function cmd_to_page.
Move the common part of these three functions to function cmd_help to
avoid code duplication.
Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Reviewed-by: Felipe Contreras <felipe.contreras@gmail.com>
Acked-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>