Merge branch 'stable-4.3' into glitch-soc/backports-4.3

Conflicts:
- `app/helpers/application_helper.rb`:
  Upstream added a helper where glitch-soc had its own, not really
  a conflict.
  Added upstream's helper.

config/routes.rb

@@ -68,7 +68,7 @@ Rails.application.routes.draw do
   scope path: '.well-known' do
     scope module: :well_known do
       get 'oauth-authorization-server', to: 'oauth_metadata#show', as: :oauth_metadata, defaults: { format: 'json' }
-      get 'host-meta', to: 'host_meta#show', as: :host_meta, defaults: { format: 'xml' }
+      get 'host-meta', to: 'host_meta#show', as: :host_meta
       get 'nodeinfo', to: 'node_info#index', as: :nodeinfo, defaults: { format: 'json' }
       get 'webfinger', to: 'webfinger#show', as: :webfinger
     end