doc refactor: streams

doc/api/streams.markdown

@@ -1,4 +1,4 @@
-## Streams
+# Streams
 
 A stream is an abstract interface implemented by various objects in Node.
 For example a request to an HTTP server is a stream, as is stdout. Streams
@@ -6,6 +6,8 @@ are readable, writable, or both. All streams are instances of `EventEmitter`.
 
 ## Readable Stream
 
+<!--type=class-->
+
 A `Readable Stream` has the following methods, members, and events.
 
 ### Event: 'data'
@@ -99,6 +101,8 @@ This keeps `process.stdout` open so that "Goodbye" can be written at the end.
 
 ## Writable Stream
 
+<!--type=class-->
+
 A `Writable Stream` has the following methods, members, and events.
 
 ### Event: 'drain'