qapi: nail down convention that Errors sections are lists

By unstated convention, Errors sections are rST lists.  Document the
convention, and make the one exception conform.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240626222128.406106-10-jsnow@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2 files changed