Return true if a password is present
This function returns true if the userinfo is present and contains a password.
assert( url_view( "http://jane%2Ddoe:pass@example.com" ).has_password() );
Constant.
Throws nothing.
userinfo    = user [ ":" [ password ] ]
user        = *( unreserved / pct-encoded / sub-delims )
password    = *( unreserved / pct-encoded / sub-delims / ":" )
true if the userinfo contains a password.
has_userinfo, encoded_password, encoded_user, encoded_userinfo, password, user, userinfo.