qapi/schema: make c_type() and json_type() abstract methods

These methods should always return a str, it's only the default abstract
implementation that doesn't. They can be marked "abstract", which
requires subclasses to override the method with the proper return type.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240315152301.3621858-9-armbru@redhat.com>
1 file changed