ui: path option to declare which revisions to push by default Now that we have a mechanism for declaring path sub-options, we can start to pile on features! Many power users have expressed frustration that bare `hg push` attempts to push all local revisions to the remote. This patch introduces the "pushrev" path sub-option to control which revisions are pushed when no "-r" argument is specified. The value of this sub-option is a revset, naturally. A future feature addition could potentially introduce a "pushnames" sub-options that declares the list of names (branches, bookmarks, topics, etc) to push by default. The entire "what to push by default" feature should probably be considered before this patch lands.