Merge commit 'c40ab43dc703be988c277d4ba6b7987a3a80e16c' into glitch-soc/merge-upstream

Conflicts:
- `app/helpers/application_helper.rb`:
  Upstream added a helper where glitch-soc had its own, not really
  a conflict.
  Added upstream's helper.
- `lib/sanitize_ext/sanitize_config.rb`:
  Upstream renamed a constant that was used slightly differently in glitch-soc.
  Renamed it as upstream did.

lib/sanitize_ext/sanitize_config.rb

@@ -21,7 +21,7 @@ class Sanitize
       gemini
     ).freeze
 
-    CLASS_WHITELIST_TRANSFORMER = lambda do |env|
+    ALLOWED_CLASS_TRANSFORMER = lambda do |env|
       node = env[:node]
       class_list = node['class']&.split(/[\t\n\f\r ]/)
 
@@ -99,7 +99,7 @@ class Sanitize
       },
 
       transformers: [
-        CLASS_WHITELIST_TRANSFORMER,
+        ALLOWED_CLASS_TRANSFORMER,
         IMG_TAG_TRANSFORMER,
         TRANSLATE_TRANSFORMER,
         UNSUPPORTED_HREF_TRANSFORMER,
@@ -163,7 +163,7 @@ class Sanitize
       add_attributes: {},
 
       transformers: [
-        CLASS_WHITELIST_TRANSFORMER,
+        ALLOWED_CLASS_TRANSFORMER,
         IMG_TAG_TRANSFORMER,
         TRANSLATE_TRANSFORMER,
         UNSUPPORTED_HREF_TRANSFORMER,