docs/devel/testing: Rename avocado_qemu.Test class

The avocado_qemu.Test class has been renamed a while back in commit
2283b627bc ("tests/avocado: Rename avocado_qemu.Test -> QemuSystemTest"),
so we should reflect this now in the documentation, too.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20240830133841.142644-44-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
1 file changed