plugins groupblog, XEP-0277: attempt to clarify the code for the comments handling:

- add or update some methods docstrings
- add GroupBlog.__fillCommentsElement to factorize the code responsible to build the comments link
- do not mix up attributes names between the item own service/node and the comments service/node

src/plugins/plugin_xep_0277.py

@@ -71,6 +71,12 @@ class XEP_0277(object):
                               doc={})
 
     def parseCommentUrl(self, node_url):
+        """Determine the fields comments_service and comments_node of a microblog data
+        from the href attribute of an entry's link element. For example this input:
+        xmpp:sat-pubsub.libervia.org?node=urn%3Axmpp%3Acomments%3A_c5c4a142-2279-4b2a-ba4c-1bc33aa87634__urn%3Axmpp%3Agroupblog%3Asouliane%libervia.org
+        will return (JID(u'sat-pubsub.libervia.org'), 'urn:xmpp:comments:_c5c4a142-2279-4b2a-ba4c-1bc33aa87634__urn:xmpp:groupblog:souliane%libervia.org')
+        @return: a tuple (JID, str)
+        """
         parsed_url = urlparse.urlparse(node_url, 'xmpp')
         service = jid.JID(parsed_url.path)
         queries = parsed_url.query.split(';')
@@ -154,7 +160,7 @@ class XEP_0277(object):
                         microblog_data['comments_node'] = node
                         break
                 except (KeyError, exceptions.DataError, RuntimeError):
-                    warning("Can't parse link")
+                    warning(_("Can't parse the link element of pubsub entry %s") % item['id'])
                     continue
         except (AttributeError, KeyError):
             error(_('Error while parsing atom entry for microblogging event'))