tests/test-parseindex2.py.out

wireproto: add media type to version 2 capabilities response

This is useful to advertise because servers reject unsupported
media types. A client may wish to speak multiple media types and
choose the one the server supports.

I doubt we'll ever use multiple media types or negotiation in core.
But during the course of developing this protocol, I may end up
making extensions that backport and forward port protocol support
as needed to support Mercurial deploys in the wild. e.g. I may
deploy support for an older protocol on a server so old clients
can continue using it.

It's worth pursuing changing the SSH protocol's upgrade mechanism
to support multiple media types as well...

Differential Revision: https://phab.mercurial-scm.org/D3299

done