virConnectGetAllDomainStats: Document two vcpu stats
virConnectGetAllDomainStats: Document two vcpu stats

When introducing vcpu.<num>.wait (v1.3.2-rc1~301) and
vcpu.<num>.halted (v2.4.0-rc1~36) the documentation was
not written.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

libvirt/libvirt,zippy2/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,zippy2/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,jardasgit/libvirt,olafhering/libvirt,jfehlig/libvirt,jardasgit/libvirt,nertpinx/libvirt,jardasgit/libvirt,jfehlig/libvirt,crobinso/libvirt,nertpinx/libvirt,crobinso/libvirt,jfehlig/libvirt,jfehlig/libvirt,olafhering/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,libvirt/libvirt