doc: remove parenthetical \r\n comment in http and http2 docs

The explanation that the HTTP requests include `\r\n` is true but not
important or relevant in these two specific contexts.

PR-URL: https://github.com/nodejs/node/pull/34178


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>