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

Conflicts:
	app/javascript/styles/mastodon-light.scss
	config/locales/en.yml
	config/locales/fr.yml
	config/locales/simple_form.pl.yml
	config/themes.yml

Conflicts resolved by deleting config/themes.yml,
marking app/javascript/styles/mastodon-light.scss as added,
and taking all new translation strings, not removing anything from
them.

app/javascript/styles/mastodon/components.scss

@@ -4737,6 +4737,8 @@ a.status-card {
   }
 }
 
+.community-timeline__section-headline,
+.public-timeline__section-headline,
 .account__section-headline {
   background: darken($ui-base-color, 4%);
   border-bottom: 1px solid lighten($ui-base-color, 8%);