Use interfaces instead of concrete classes in the documentation react…

…php#38 (comment)

README.md

@@ -64,15 +64,15 @@ access fields otherwise available through `proc_get_status()`.
 ### Stream Properties
 
 Once a process is started, its I/O streams will be constructed as instances of
-`React\Stream\ReadableResourceStream` and `React\Stream\WritableResourceStream`. Before `start()` is called, these properties are `null`.
+`React\Stream\ReadableStreamInterface` and `React\Stream\WritableStreamInterface`. Before `start()` is called, these properties are `null`.
 Once a process terminates, the streams will become closed but not unset.
 
 * `$stdin`
 * `$stdout`
 * `$stderr`
 
 Each of these implement the underlying
-[`ReadableResourceStream`](https://github.com/reactphp/stream#readablestreaminterface) or [`WritableResourceStream`](https://github.com/reactphp/stream#writablestreaminterface)
+[`ReadableStreamInterface`](https://github.com/reactphp/stream#readablestreaminterface) or [`WritableStreamInterface`](https://github.com/reactphp/stream#writablestreaminterface)
 and you can use any of their events and methods as usual:
 
 ```php
@@ -98,7 +98,7 @@ $process->stdin->end($data = null);
 ```
 
 For more details, see the
-[`ReadableResourceStream`](https://github.com/reactphp/stream#readablestreaminterface) and [`WritableResourceStream`](https://github.com/reactphp/stream#writablestreaminterface).
+[`ReadableStreamInterface`](https://github.com/reactphp/stream#readablestreaminterface) and [`WritableStreamInterface`](https://github.com/reactphp/stream#writablestreaminterface).
 
 ### Command