doc: add socket.readyState

+ description of `socket.readyState`

Note: YAML tag found in commit e697cfb

Co-authored-by: Michael Auderer <mike@silverstone.io>

PR-URL: #35262
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/net.md

@@ -964,6 +964,20 @@ written out, which may not be immediately.
 See `Writable` stream [`write()`][stream_writable_write] method for more
 information.
 
+### `socket.readyState`
+<!-- YAML
+added: v0.5.0
+-->
+
+* {string}
+
+This property represents the state of the connection as a string.
+
+* If the stream is connecting `socket.readyState` is `opening`.
+* If the stream is readable and writable, it is `open`.
+* If the stream is readable and not writable, it is `readOnly`.
+* If the stream is not readable and writable, it is `writeOnly`.
+
 ## `net.connect()`
 
 Aliases to