Fixes html encoding of some characters by bleach.

app/apps/api/serializers.py

 import bleach
 import logging
+import html
 
 from django.conf import settings
 from django.db.utils import IntegrityError
@@ -162,7 +163,9 @@ class LineTranscriptionSerializer(serializers.ModelSerializer):
                   'versions', 'version_author', 'version_source', 'version_updated_at')
 
     def cleanup(self, data):
-        return bleach.clean(data, tags=['em', 'strong', 's', 'u'], strip=True)
+        nd = bleach.clean(data, tags=['em', 'strong', 's', 'u'], strip=True)
+        nd = html.unescape(nd)
+        return nd
 
     def validate_content(self, content):
         return self.cleanup(content)