next: prompt user to choose child in ambiguity in `hg next --evolve` This patch makes `hg next --evolve` prompt user to choose a child to evolve and update when multiple of them exists. This is improvement over previous behavior where we used to error out saying ambiguous next unstable changeset and told user to manually use `hg evolve -r rev`. While writing this patch, I am personally very happy to have this feature as I have encountered this stage many times and I wanted `next --evolve` to take care of that. It uses the revselectionprompt thing added in earlier patches.

-------------------------
Evolve Commands Reference
-------------------------

.. highlight:: none

amend
-----

.. hghelp:: amend

evolve
------

.. hghelp:: evolve

fold
----

.. hghelp:: fold

metaedit
--------

.. hghelp:: metaedit

next
----

.. hghelp:: next

obslog
------

.. hghelp:: obslog

pdiff
-----

.. hghelp:: pdiff

previous
--------

.. hghelp:: previous

prune
-----

.. hghelp:: prune

pstatus
-------

.. hghelp:: pstatus

split
-----

.. hghelp:: split

touch
-----

.. hghelp:: touch

uncommit
--------

.. hghelp:: uncommit