Clean up 3-way decision

[frivoal]

Currently, the charter refinement phase ends in one of 3 ways: extension, abandonment, or AC Review. Each way can be objected to, but for two of them, the result is a little weird.

If people object to the AC review being initiated, that's fine, because we get a council to deal with the objection(s) at the end of the Review, and that's appropriate.

However, in case of an objection to abandon: should we go to AC Review immediately (because the objectors are unhappy with giving up on something that's good), or should we extend (because the objectors agree that it's not ready, but are convinced consensus can be found)? Same problem with objections to extending: do we give up (because it's alleged to being an abusive extension of something hopeless), or do we go to review immediately?

The current text is not entirely broken, since it does define a course of action, but what it says isn't great.