Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- `Gemfile.lock`:
  No real conflict, glitch-soc-only dependency (redcarpet) too close to an
  upstream one (rdf-normalize)
- `README.md`:
  we have different READMEs, discarded upstream's changes
- `app/views/admin/custom_emojis/index.html.haml`:
  No real conflict, different context because of glitch-soc theming
- `lib/mastodon/statuses_cli.rb`:
  Upstream added code to keep bookmarked statuses, we were already doing so
  with slightly different code. Discarded upstream's changes.
- `package.json`:
  No real conflict, glitch-soc-only dependency (favico.js) too close to
  an upstream one

config/locales/simple_form.en.yml

@@ -163,14 +163,14 @@ en:
         text: Why do you want to join?
       notification_emails:
         digest: Send digest e-mails
-        favourite: Someone favourited your status
-        follow: Someone followed you
-        follow_request: Someone requested to follow you
-        mention: Someone mentioned you
-        pending_account: New account needs review
-        reblog: Someone boosted your status
-        report: New report is submitted
-        trending_tag: An unreviewed hashtag is trending
+        favourite: Send e-mail when someone favourites your status
+        follow: Send e-mail when someone follows you
+        follow_request: Send e-mail when someone requests to follow you
+        mention: Send e-mail when someone mentions you
+        pending_account: Send e-mail when a new account needs review
+        reblog: Send e-mail when someone boosts your status
+        report: Send e-mail when a new report is submitted
+        trending_tag: Send e-mail when an unreviewed hashtag is trending
       tag:
         listable: Allow this hashtag to appear in searches and on the profile directory
         name: Hashtag