Merge commit '598ae4f2da86029b1c3c3e35e64b89873037b598' into glitch-soc/merge-upstream

Conflicts:
- `config/routes/api.rb`:
  Upstream added an endpoint, textually close to a glitch-soc-only endpoint.
  Ported upstream changes.

config/routes/api.rb

@@ -169,6 +169,7 @@ namespace :api, format: false do
       collection do
         post :clear
         delete :destroy_multiple
+        get :unread_count
       end
 
       member do
@@ -338,6 +339,7 @@ namespace :api, format: false do
     resources :notifications, only: [:index, :show] do
       collection do
         post :clear
+        get :unread_count
       end
 
       member do