branch page does not link to its series

<https://code.edge.launchpad.net/~mbp/bzr/bzr.1.12> is the branch associated with the bzr/1.12 series. There should be an indication that this is so, and a link to the series. There is not.

It does show the url "lp:bzr/1.12", but that's pretty subtle, and there's no clickable link.

This should be shown whatever the status of the series. It might be nice if the series state (mature, obsolete, etc) was shown.