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

Conflicts:
- `app/controllers/api/v1/statuses_controller.rb`:
  Conflict due to upstream adding a new parameter (with_rate_limit),
  too close to glitch-soc's own additional parameter (content_type).
  Added upstream's parameter.
- `app/services/post_status_service.rb`:
  Conflict due to upstream adding a new parameter (rate_limit),
  too close to glitch-soc's own additional parameter (content_type).
  Added upstream's parameter.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Conflict due to us not exposing theme settings here (as we have
  a different flavour/skin menu).
  Took upstream change, while still not exposing theme settings.
- `config/webpack/shared.js`:
  Coding style fixes for a part we have rewritten.
  Discarded upstream changes.

app/controllers/api/v2/search_controller.rb

@@ -8,8 +8,6 @@ class Api::V2::SearchController < Api::BaseController
   before_action -> { doorkeeper_authorize! :read, :'read:search' }
   before_action :require_user!
 
-  respond_to :json
-
   def index
     @search = Search.new(search_results)
     render json: @search, serializer: REST::SearchSerializer