doc: "mon destroy" accepts multiple nodes
doc: "mon destroy" accepts multiple nodes

Signed-off-by: Kefu Chai <a4b264ee037c625052534d60505bfd0db4776ac4@redhat.com>

ceph/ceph-deploy,osynge/ceph-deploy,Vicente-Cheng/ceph-deploy,isyippee/ceph-deploy,osynge/ceph-deploy,isyippee/ceph-deploy,branto1/ceph-deploy,ghxandsky/ceph-deploy,zhouyuan/ceph-deploy,SUSE/ceph-deploy,shenhequnying/ceph-deploy,ghxandsky/ceph-deploy,shenhequnying/ceph-deploy,zhouyuan/ceph-deploy,ceph/ceph-deploy,branto1/ceph-deploy,imzhulei/ceph-deploy,SUSE/ceph-deploy-to-be-deleted,trhoden/ceph-deploy,codenrhoden/ceph-deploy,trhoden/ceph-deploy,Vicente-Cheng/ceph-deploy,SUSE/ceph-deploy-to-be-deleted,SUSE/ceph-deploy,codenrhoden/ceph-deploy,imzhulei/ceph-deploy