27393c33 qapi: keep names in 'CpuInstanceProperties' in sync with struct CPUCore
added -id suffix to property names but forgot to fix example in qmp-commands.hx

Fix example to have 'core-id' instead of 'core' to match current code

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>