Documentation: kvm: organize capabilities in the right section

JIRA: https://issues.redhat.com/browse/RHEL-82917

commit af33928
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Tue Apr 1 14:57:39 2025 +0200

    Documentation: kvm: organize capabilities in the right section

    Categorize the capabilities correctly.  Section 6 is for enabled vCPU
    capabilities; section 7 is for enabled VM capabilities; section 8 is
    for informational ones.

    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>

Author: Maxim Levitsky