doc, stream: readable._destroy() description is missing in the stream.md

[vsemozhetbyt]

• Subsystem: doc, stream

There is a link to readable._destroy() in the stream.md after 330c8d7, but there is no readable._destroy() description in the Implementing a Readable Stream part.

cc @mcollina

[mcollina]

Definitely, I'll get this added asap. This is a also a first good contribution, if someone wants to take it.

The content for writable._destroy()  needs to be copied over to readable._destroy(). It's the same logic.

[vsemozhetbyt]

Refs: #15316