doc: clarify documentation of pipes and zlib objects

Document how pipes can be chained in readable.pipe().
Document that zlib.Zlib inherits from stream.Transform.

PR-URL: https://github.com/nodejs/node/pull/22354
Fixes: https://github.com/nodejs/node/issues/22341


Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>