doc/api: listed server.listen() parameters and done some minor correc…

…tions

listed server.listen() optional parameters that are used in examples but
not documented and corrected some misleading commas.
 Changes :
  modified : doc/api/http.md : updated server.listen()
  modified : doc/api/fs.md
  modified : doc/api/stream.md

doc/api/http.md

@@ -1290,7 +1290,7 @@ event is emitted on the server object, and (by default) the socket is destroyed.
 See [`server.timeout`][] for more information on how timeout behavior can be
 customized.
 
-### `server.listen([Port,] [host,] [callback])`
+### `server.listen(Port [,host] [,callback])`
 
 * `Port` {Number}
 * `Host` {String}