doc: update stream.md "Organization of this Document"

Revise the text of "Organization of this Document" in stream.md for
simplicity.

PR-URL: #28601
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: Trott

doc/api/stream.md

@@ -28,10 +28,9 @@ the `stream` module directly.
 
 ## Organization of this Document
 
-This document is divided into two primary sections with a third section for
-additional notes. The first section explains the elements of the stream API that
-are required to *use* streams within an application. The second section explains
-the elements of the API that are required to *implement* new types of streams.
+This document contains two primary sections and a third section for notes. The
+first section explains how to use existing streams within an application. The
+second section explains how to create new types of streams.
 
 ## Types of Streams