histedit: use `get_unique_push_path`

Same as for `pathbomb`, this code does not support multiple destinations yet. It might in the future, probably with code put in common with patchwork, but for now lets use the dedicated API.

Differential Revision: https://phab.mercurial-scm.org/D10408

hgext/histedit.py

@@ -1041,11 +1041,12 b' def findoutgoing(ui, repo, remote=None, '
     Used by initialization code"""
     if opts is None:
         opts = {}
-    dest = ui.expandpath(remote or b'default-push', remote or b'default')
-    dest, branches = urlutil.parseurl(dest, None)[:2]
+    path = urlutil.get_unique_push_path(b'histedit', repo, ui, remote)
+    dest = path.pushloc or path.loc
+
     ui.status(_(b'comparing with %s\n') % urlutil.hidepassword(dest))
 
-    revs, checkout = hg.addbranchrevs(repo, repo, branches, None)
+    revs, checkout = hg.addbranchrevs(repo, repo, (path.branch, []), None)
     other = hg.peer(repo, opts, dest)
 
     if revs: