relnotes: copy contents of "next" to "5.8" and clear "next"
The same procedure as every year^Wcycle.
Unlike previous cycles, I haven't actually recorded the copy because
we don't want to propagate further changes in "next" (from the stable
branch) to "5.8".
Differential Revision: https://phab.mercurial-scm.org/D10500
== New Features ==
== Default Format Change ==
These changes affects newly created repositories (or new clone) done with
Mercurial 5.8.
== New Experimental Features ==
== Bug Fixes ==
== Backwards Compatibility Changes ==
== Internal API Changes ==