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

Conflicts:
- `README.md`:
  Minor upstream change, our README is completely different.
  Kept ours.
- `lib/tasks/assets.rake`:
  glitch-soc has extra code to deal with its theming system,
  upstream changed a line that exists in glitch-soc.
  Applied upstream changes.

app/models/concerns/omniauthable.rb

@@ -97,8 +97,7 @@ module Omniauthable
     def ensure_valid_username(starting_username)
       starting_username = starting_username.split('@')[0]
       temp_username = starting_username.gsub(/[^a-z0-9_]+/i, '')
-      validated_username = temp_username.truncate(30, omission: '')
-      validated_username
+      temp_username.truncate(30, omission: '')
     end
   end
 end

app/models/concerns/remotable.rb

@@ -27,11 +27,11 @@ module Remotable
             public_send("#{attachment_name}=", ResponseWithLimit.new(response, limit))
           end
         rescue Mastodon::UnexpectedResponseError, HTTP::TimeoutError, HTTP::ConnectionError, OpenSSL::SSL::SSLError => e
-          Rails.logger.debug "Error fetching remote #{attachment_name}: #{e}"
+          Rails.logger.debug { "Error fetching remote #{attachment_name}: #{e}" }
           public_send("#{attachment_name}=", nil) if public_send("#{attachment_name}_file_name").present?
           raise e unless suppress_errors
         rescue Paperclip::Errors::NotIdentifiedByImageMagickError, Addressable::URI::InvalidURIError, Mastodon::HostValidationError, Mastodon::LengthValidationError, Paperclip::Error, Mastodon::DimensionsValidationError, Mastodon::StreamValidationError => e
-          Rails.logger.debug "Error fetching remote #{attachment_name}: #{e}"
+          Rails.logger.debug { "Error fetching remote #{attachment_name}: #{e}" }
           public_send("#{attachment_name}=", nil) if public_send("#{attachment_name}_file_name").present?
         end