tests/qapi-schema: Demonstrate command and event doc comment bugs

Add negative tests doc-bad-boxed-command-arg and doc-bad-event-arg to
cover boxed and no arguments.  They demonstrate insufficient doc
comment checking.

Update positive test doc-good to cover boxed event arguments.  It
demonstrates the generated doc comment misses arguments.

These bugs will be fixed later in this series.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20191024110237.30963-3-armbru@redhat.com>
10 files changed