Docs - Add doc for traverse.traverse method

src/traverse.ts

@@ -1,6 +1,20 @@
 // import { isNodeSimple } from './utils';
 import { FiberNode } from "./mocked-types";
 
+/**
+ * Traverse nodes recursively in depth-first manner, starting from a start node.
+ *
+ * This is the default and basic traversal method, which covers basic use cases.
+ * You can't do advanced things like change the order of traversal, skip or cancel traversal after any node, etc.
+ * For more advanced usecases, see {@link traverseGenerator}
+ *
+ * @example
+ * ```js
+ * // calls fn for each node inside startNode
+ * traverse(startNode, fn);
+ * ```
+ *
+ */
 function traverse(node: FiberNode, fn: (node: FiberNode) => any) {
   fn.call(null, node);