Subscription: better feature description (#11676)

Closes #11414

Author: stsewd

readthedocs/subscriptions/constants.py

@@ -23,7 +23,7 @@
 
 FEATURE_TYPES = (
     (TYPE_CNAME, _("Custom domain")),
-    (TYPE_CDN, _("CDN public documentation")),
+    (TYPE_CDN, _("CDN for public documentation")),
     (TYPE_SSL, _("Custom SSL configuration")),
     (TYPE_SUPPORT, _("Support SLA")),
     (TYPE_PRIVATE_DOCS, _("Private documentation")),