Merge commit '6a4d14b178fc00de989b4a2758f2a1e4adf5ed33' into glitch-soc/merge-upstream

Conflicts:
- `lib/sanitize_ext/sanitize_config.rb`:
  Glitch-soc allows a wider range of HTML than upstream.
  Upstream added `:all => %w(lang)`, which was not supported by glitch-soc,
  added it there too.

lib/sanitize_ext/sanitize_config.rb

@@ -117,6 +117,7 @@ class Sanitize
       elements: %w(p br span a abbr del s pre blockquote code b strong u sub sup i em h1 h2 h3 h4 h5 ul ol li ruby rt rp),
 
       attributes: {
+        :all => %w(lang),
         'a' => %w(href rel class title translate),
         'abbr' => %w(title),
         'span' => %w(class translate),