When citing other Git commands, rather than merely formatting them with
a fixed-width typeface, improve the reader experience by linking to them
directly via `linkgit:`.
Suggested-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>