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

cache.h

@@ -1003,14 +1003,19 @@ struct ref {
 	unsigned char old_sha1[20];
 	unsigned char new_sha1[20];
 	char *symref;
-	unsigned int force:1,
+	unsigned int
+		force:1,
+		requires_force:1,
 		merge:1,
 		nonfastforward:1,
+		not_forwardable:1,
+		update:1,
 		deletion:1;
 	enum {
 		REF_STATUS_NONE = 0,
 		REF_STATUS_OK,
 		REF_STATUS_REJECT_NONFASTFORWARD,
+		REF_STATUS_REJECT_ALREADY_EXISTS,
 		REF_STATUS_REJECT_NODELETE,
 		REF_STATUS_UPTODATE,
 		REF_STATUS_REMOTE_REJECT,