doc: fix typo in stream.md

Marc Hernández Cabot · noviluni · commit a437d9d8ded2 · 2017-07-19T19:44:07.000+02:00
Fixes: #14362
diff --git a/doc/api/stream.md b/doc/api/stream.md
@@ -2035,7 +2035,7 @@ user programs.
 
 `transform._transform()` is never called in  parallel; streams implement a
 queue mechanism, and to receive the next chunk, `callback` must be
-called, either synchronously or asychronously.
+called, either synchronously or asynchronously.
 
 #### Class: stream.PassThrough
 
