rebase: tell when reopening a closed branch head

Give same 'reopening closed branch head X' message as commit gives.

hgext/rebase.py

@@ -289,6 +289,9 b' def rebase(ui, repo, **opts):'
                                                            inclusive=True)
                 external = externalparent(repo, state, targetancestors)
 
+            if dest.closesbranch() and not keepbranchesf:
+                ui.status(_('reopening closed branch head %s\n') % dest)
+
         if keepbranchesf:
             # insert _savebranch at the start of extrafns so if
             # there's a user-provided extrafn it can clobber branch if

tests/test-rebase-named-branches.t

@@ -239,6 +239,17 b' Rebasing descendant onto ancestor across'
   |/
   @  0: 'A'
   
+
+Reopen branch by rebase
+
+  $ hg up -qr3
+  $ hg branch -q b
+  $ hg ci -m 'create b'
+  $ hg ci -m 'close b' --close
+  $ hg rebase -b 8 -d b
+  reopening closed branch head ea9de14a36c6
+  saved backup bundle to $TESTTMP/a1/.hg/strip-backup/*-backup.hg (glob)
+
   $ cd ..
 
 Rebase to other head on branch