Merge branch 'cr/push-force-tag-update'

Merge branch 'cr/push-force-tag-update'

Require "-f" for push to update a tag, even if it is a fast-forward.

* cr/push-force-tag-update:
  push: allow already-exists advice to be disabled
  push: rename config variable for more general use
  push: cleanup push rules comment
  push: clarify rejection of update to non-commit-ish
  push: require force for annotated tags
  push: require force for refs under refs/tags/
  push: flag updates that require force
  push: keep track of "update" state separately
  push: add advice for rejected tag reference
  push: return reject reasons as a bitset