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/javascript/mastodon/actions/server.js

@@ -5,6 +5,10 @@ export const SERVER_FETCH_REQUEST = 'Server_FETCH_REQUEST';
 export const SERVER_FETCH_SUCCESS = 'Server_FETCH_SUCCESS';
 export const SERVER_FETCH_FAIL    = 'Server_FETCH_FAIL';
 
+export const SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST = 'SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST';
+export const SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS = 'SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS';
+export const SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL    = 'SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL';
+
 export const EXTENDED_DESCRIPTION_REQUEST = 'EXTENDED_DESCRIPTION_REQUEST';
 export const EXTENDED_DESCRIPTION_SUCCESS = 'EXTENDED_DESCRIPTION_SUCCESS';
 export const EXTENDED_DESCRIPTION_FAIL    = 'EXTENDED_DESCRIPTION_FAIL';
@@ -37,6 +41,29 @@ const fetchServerFail = error => ({
   error,
 });
 
+export const fetchServerTranslationLanguages = () => (dispatch, getState) => {
+  dispatch(fetchServerTranslationLanguagesRequest());
+
+  api(getState)
+    .get('/api/v1/instance/translation_languages').then(({ data }) => {
+      dispatch(fetchServerTranslationLanguagesSuccess(data));
+    }).catch(err => dispatch(fetchServerTranslationLanguagesFail(err)));
+};
+
+const fetchServerTranslationLanguagesRequest = () => ({
+  type: SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST,
+});
+
+const fetchServerTranslationLanguagesSuccess = translationLanguages => ({
+  type: SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS,
+  translationLanguages,
+});
+
+const fetchServerTranslationLanguagesFail = error => ({
+  type: SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL,
+  error,
+});
+
 export const fetchExtendedDescription = () => (dispatch, getState) => {
   dispatch(fetchExtendedDescriptionRequest());