Update the ingress gateway documentation to remove the note stating
that a port must be specified for values in the `hosts` field when
the ingress gateway is listening on a non-standard HTTP port.

Specifying a port was required in Consul 1.8.0, but that requirement
was removed in 1.8.1 with hashicorp/consul#8190 which made Consul
include the port number when constructing the Envoy configuration.

Related Consul docs PR: hashicorp/consul#10827