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

Conflicts:
- `README.md`:
  Upstream changed their README, we have our own.
  Kept ours.
- `app/helpers/application_helper.rb`:
  Minor code style fix upstream, on a line that is different in glitch-soc
  due to the different theming system.
  Applied the code style fix to our own code.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Code style fix on a line next to lines exclusive to glitch-soc.
  Applied upstream changes.
- `yarn.lock`:
  Upstream updated a dependency textually close to a glitch-soc-only
  dependency.
  Updated the dependency like upstream did.

app/views/auth/sessions/new.html.haml

@@ -19,7 +19,7 @@
     .actions
       = f.button :button, t('auth.login'), type: :submit
 
-- if devise_mapping.omniauthable? and resource_class.omniauth_providers.any?
+- if devise_mapping.omniauthable? && resource_class.omniauth_providers.any?
   .simple_form.alternative-login
     %h4= omniauth_only? ? t('auth.log_in_with') : t('auth.or_log_in_with')