i18n: remote: add comment for translators

Add comment drawing translator attention in order to align "Push
URL:" and "Fetch URL:" fields translation of git remote show output.

Aligning both fields makes the output more appealing and easier to
grasp.

Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
