discovery: improve "note: unsynced remote changes!" warning This message frequently caused confusion. "unsynced" is not a well established user-facing concept in Mercurial and the message was not very specific or helpful. Instead, show a message like: remote has heads on branch 'default' that are not known locally: 6c0482d977a3 This message will also (when relevant) be shown before aborting on "push creates new remote head". A similar (but actually very different) message was addressed in 6b618aa08b6e.