qapi/char: Supply missing member documentation

Since we neglect to document several members of ChardevBackendKind,
their description in the QEMU QMP Reference manual is "Not
documented".  Fix that, and improve the existing member documentation.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240911112545.2248881-2-armbru@redhat.com>
2 files changed