cache: introduce a changelogsourcebase class
This abstract class will help code that need a cache tracking the changelog
content (eg: the branchmap cache). The cache key used is the same as what the
branchmap uses.
This code was headed for core during the 4.3 cycle but never made it there. So
we starts with a copy in the evolve repository.
-------------------------
Evolve Commands Reference
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.. 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