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

- `.env.production.sample`:
  Our sample config file is very different from upstream since it is much more
  complete. Upstream added documentation for a few env variables.
  Copied the new variables/documentation from upstream.
- `app/lib/feed_manager.rb`:
  Upstream added a timeline type (hashtags), while glitch-soc already had an
  extra one (direct messages). Not really a conflict but textually close
  changes.
  Ported upstream's changes.
- `app/models/custom_emoji.rb`:
  Upstream upped the custom emoji size limit, while glitch-soc had configurable
  limits.
  Upped the default limits accordingly.
- `streaming/index.js`:
  Upstream reworked how hastags were normalized. Minor conflict due to
  glitch-soc's handling of instance-local posts.
  Ported upstream's changes.

config/initializers/inflections.rb

@@ -24,6 +24,7 @@ ActiveSupport::Inflector.inflections(:en) do |inflect|
   inflect.acronym 'RSS'
   inflect.acronym 'REST'
   inflect.acronym 'URL'
+  inflect.acronym 'ASCII'
 
   inflect.singular 'data', 'data'
 end