Add setCurrent() method to Page Collection

#531

system/src/Grav/Common/Page/Collection.php

@@ -145,6 +145,18 @@ class Collection extends Iterator implements PageCollectionInterface
         return $this;
     }
 
+    /**
+     * Set current page.
+     */
+    public function setCurrent(string $path): void
+    {
+        reset($this->items);
+
+        while (key($this->items) !== $path && key($this->items) !== null) {
+            next($this->items);
+        }
+    }
+
     /**
      * Returns current page.
      *