Merge commit '4896d2c4c6d3bd6b878c5a075b6611c65d4203b2' into glitch-soc/merge-upstream

Conflicts:
- `app/views/settings/preferences/appearance/show.html.haml`:
  Upstream changed stuff too close to glitch-soc's theming system changes.
  Applied upstream's changes.
- `streaming/index.js`:
  Upstream refactored a bunch of stuff where our code was different due to
  local-only posts.
  Applied upstream's changes while taking care of local-only posts.

spec/models/tag_spec.rb

@@ -84,6 +84,10 @@ RSpec.describe Tag do
       expect(subject.match('this is #ａｅｓｔｈｅｔｉｃ').to_s).to eq '#ａｅｓｔｈｅｔｉｃ'
     end
 
+    it 'matches ＃ｆｏｏ' do
+      expect(subject.match('this is ＃ｆｏｏ').to_s).to eq '＃ｆｏｏ'
+    end
+
     it 'matches digits at the start' do
       expect(subject.match('hello #3d').to_s).to eq '#3d'
     end