Add doc for includeWhen

Author: pierreneter

blade.md

@@ -337,6 +337,13 @@ Of course, if you attempt to `@include` a view which does not exist, Laravel wil
 
     @includeIf('view.name', ['some' => 'data'])
 
+If you want to `@include` a view that depends on a condition you can use `@includeWhen`:
+
+    @php
+        $display = true;
+    @endphp
+    @includeWhen($display, 'view.name', ['some' => 'data'])
+
 > {note} You should avoid using the `__DIR__` and `__FILE__` constants in your Blade views, since they will refer to the location of the cached, compiled view.
 
 <a name="rendering-views-for-collections"></a>