Fix spelling mistakes

doc/api/streams.markdown

@@ -125,7 +125,7 @@ Emitted on error with the exception `exception`.
 
 Emitted when the underlying file descriptor has been closed.
 
-### stream.writeable
+### stream.writable
 
 A boolean that is `true` by default, but turns `false` after an `'error'`
 occurred or `end()` / `destroy()` was called.

doc/api/util.markdown

@@ -39,12 +39,12 @@ Example of inspecting all properties of the `util` object:
     console.log(util.inspect(util, true, null));
 
 
-### util.pump(readableStream, writeableStream, [callback])
+### util.pump(readableStream, writableStream, [callback])
 
 Experimental
 
 Read the data from `readableStream` and send it to the `writableStream`.
-When `writeableStream.write(data)` returns `false` `readableStream` will be
+When `writableStream.write(data)` returns `false` `readableStream` will be
 paused until the `drain` event occurs on the `writableStream`. `callback` gets
 an error as its only argument and is called when `writableStream` is closed or
 when an error occurs.