website: mention node name for "agent/force-leave" HTTP endpoint (#4542)
website: mention node name for "agent/force-leave" HTTP endpoint (#4542)

* Adjust documentation for agent/force-leave endpoint

A node must be specified when calling agent/force-leave.
See:
 - https://github.com/hashicorp/consul/blob/master/agent/http_oss.go#L25
 - https://github.com/hashicorp/consul/blob/master/agent/agent_endpoint.go#L323
 - https://github.com/hashicorp/consul/blob/master/agent/agent.go#L1442

However, the documentation does not specify it.
Note that Consul returns "301 Moved Permanently v1/agent/force-leave/" when sending PUT request on "v1/agent/force-leave".

* Switch from node id to node name

hashicorp/consul,hashicorp/consul,vamage/consul,scalp42/consul,kingland/consul,hashicorp/consul,vamage/consul,42wim/consul,42wim/consul,kingland/consul,scalp42/consul,youhong316/consul,kingland/consul,scalp42/consul,42wim/consul,kingland/consul,hashicorp/consul,42wim/consul,youhong316/consul,youhong316/consul,youhong316/consul,youhong316/consul,42wim/consul,vamage/consul,scalp42/consul,vamage/consul,scalp42/consul,kingland/consul,vamage/consul