Refer to description of "http" and "https" direct access

[royfielding]

In Section 7.3.3 (as noted by #914)

If no proxy is applicable, a typical client will invoke a handler
routine, usually specific to the target URI's scheme, to connect
directly to an origin for the target resource. How that is
accomplished is dependent on the target URI scheme and defined by its
associated specification.

This document is the relevant specification for the "http" and "https"
URI schemes; a section reference to the corresponding procedures might
be in order.

[royfielding]

This was already implied, but it does read better if we close the loop on routing by sending the request message with the identified request target.