doc: add information for IncomingMessage.destroy()

Add documentation for `http.IncomingMessage.prototype.destroy()`.

Fixes: nodejs#4226

doc/api/http.md

@@ -910,6 +910,14 @@ following additional events, methods, and properties.
 Indicates that the underlying connection was closed.
 Just like `'end'`, this event occurs only once per response.
 
+### message.destroy(error)
+
+* `error` {Error}
+
+Calls `.destroy()` on the socket that received the `IncomingMessage`. If `error`
+is provided, an `'error'` event is fired and `error` is passed as an argument to
+any listeners on the event.
+
 ### message.headers
 
 The request/response headers object.