fix($forEachChunkModule): fix typo where chunk was call cb

Author: faceyspacey

README.md

@@ -93,8 +93,8 @@ Here's the sort of CSS you can expect to serve:
 	<!-- stylsheets that will be requested when import() on user navigation is called -->
 	<script>
 		window.__CSS_CHUNKS__ = {
-		Foo: '/static/Foo.css',
-		Bar: '/static/Bar.css'
+			Foo: '/static/Foo.css',
+			Bar: '/static/Bar.css'
 		}
 	</script>
 </body>

index.js

@@ -30,7 +30,7 @@ function forEachChunkModule( chunk, cb ) {
 
 	// webpack >= 3.x.x
 	if ( typeof chunk.forEachModule === 'function' ) {
-		cb.forEachModule( cb );
+		chunk.forEachModule( cb );
 	}
 	else {
 		// webpack < 3.x.x