Go into more details about the various types of valid expressions
in a qapi schema, including tweaks to document fixes being done
later in the current patch series. Also fix some stale and missing
documentation in the QMP specification.
Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>