evolve: add an `--update` flag to `hg evolve` command This patch adds a new `--update` flag which defaults to True. The update flag updates the working directory to the head of evolved revisions after `hg evolve` command. This flag can be used to not update your working directory after `hg evolve` which has been one of the biggest feature request from fig team at Google. To not update your working directory, the user can do `hg evolve --no-update`. If the working directory get obsoleted by evolve command, it will update to the successor. This patch also adds some basic tests for the flag introduced.

-------------------------
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