GitLab closes these issues automatically only when the destination
branch is the default branch, i.e. `master` currently:
https://docs.gitlab.com/ee/user/project/issues/managing_issues.html#closing-issues-automatically

I'm wondering if we should make the `stable` or `devel` branch our default
branch (assuming we merge more branches into these branches than into `master`),
but for now let's workaround the problem via documentation.

In passing, this commit starts making the submit/review/merge doc less focused
on code changes. This needs more work.

In passing, I'm removing a few obsolete ones.

For details, see this email thread:

  [Tails-dev] [Proposal] Redmine workflow simplification: drop "Fix committed" status
  https://lists.autistici.org/message/20191024.090149.76eba7c8.en.html

Currently translated at 17.7% (11 of 62 strings)

Translation: Tails/wiki/src/news/version_3.14.1.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcnewsversion_3141po/pt/

Currently translated at 39.0% (16 of 41 strings)

Translation: Tails/wiki/src/news/version_3.11.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcnewsversion_311po/it/

Reviewing guidelines: document how to check APT overlay suites without direct access to our reprepro instance.

We now have reviewers without commit/upload rights.

And while I'm at it, replace obsolete mention of "the APT suite" with up-to-date
instructions: branches now need to explicitly enable APT overlays.

i.e. Message-Id: <87a7hkk19g.fsf@manticora>

Some teams want to experiment and start using GitLab for code reviews,
let's allow it and see how it goes.

lamby authored Jan 14, 2019 and intrigeri committed Jan 14, 2019

Closes: #16358

refs: https://mailman.boum.org/pipermail/tails-dev/2016-November/011034.html

Closes: #11202

I'm not 100% sure it's a typo, but I've never tried it without the hyphen, so
let's not risk it, and let's be consistent with the rest of this doc.

These notes are actually useful for reviewers, more than for code contributors.