Return the host
<include/boost/url/authority_view.hpp>
template<class StringToken = string_token::return_string>
StringToken::result_type
host_address(StringToken&& token) const;
The value returned by this function depends on the type of host returned from the function host_type .
assert( url_view( "https://[1::6:c0a8:1]/" ).host_address() == "1::6:c0a8:1" );
host = IP-literal / IPv4address / reg-name
IP-literal = "[" ( IPv6address / IPvFuture ) "]"
reg-name = *( unreserved / pct-encoded / "-" / ".")