Update enzyme/enzyme.d.ts – forEach iterator function takes index as second argument (#13243)

* Update enzyme/enzyme-1.2.0.d.ts – forEach iterator function takes index as second argument

* Update enzyme-1.2.0.d.ts

Make index optional in forEach

enzyme/enzyme-1.2.0.d.ts

@@ -253,9 +253,9 @@ declare module "enzyme" {
          *
          * Returns itself.
          * @param fn A callback to be run for every node in the collection. Should expect a ShallowWrapper as the first
-         *              argument, and will be run with a context of the original instance.
+         *              argument, index as a second, and will be run with a context of the original instance.
          */
-        forEach(fn: (wrapper: this) => any): this;
+        forEach(fn: (wrapper: this, index?: number) => any): this;
 
         /**
          * Maps the current array of nodes to another array. Each node is passed in as a ShallowWrapper to the map
@@ -470,4 +470,4 @@ declare module "enzyme" {
     export function describeWithDOM(description: String, fn: Function): void;
 
     export function spyLifecycle(component: typeof Component): void;
-}
+}