wrapfunction: use sysstr instead of bytes as argument in "highlight"
This is as valid and simpler, it will help us to eventually get ride of
`safehasattr`.
= Mercurial XXX =
== New Features ==
== Default Format Change ==
These changes affect newly created repositories (or new clones) done with
Mercurial XXX.
== New Experimental Features ==
== Bug Fixes ==
== Backwards Compatibility Changes ==
== Internal API Changes ==
== Miscellaneous ==