fix mock and prop description

packages/block-editor/src/components/block-breadcrumb/stories/index.story.js

@@ -13,32 +13,34 @@ import { ExperimentalBlockEditorProvider } from '../../provider';
 // For the purpose of this story, we need to register the core blocks samples.
 registerCoreBlocks();
 const blocks = [
-	// vertical
 	createBlock( 'core/group', {}, [
-		createBlock( 'core/paragraph' ),
-		createBlock( 'core/paragraph' ),
-		createBlock( 'core/paragraph' ),
+		createBlock( 'core/group', {}, [ createBlock( 'core/paragraph' ) ] ),
 	] ),
 ];
 
+const clientId = blocks[ 0 ].innerBlocks[ 0 ].innerBlocks[ 0 ].clientId;
+
 const selection = {
 	selectionEnd: {
-		clientId: blocks[ 0 ].innerBlocks[ 0 ].clientId,
+		clientId,
 	},
 	selectionStart: {
-		clientId: blocks[ 0 ].innerBlocks[ 0 ].clientId,
+		clientId,
 	},
 };
 
+/**
+ * The block breadcrumb trail displays the hierarchy of the current block selection as a breadcrumb. It also allows, using this hierarchy, to navigate to the parent elements of the current block selection. It is located at the very bottom of the editor interface.
+ */
 const meta = {
 	title: 'BlockEditor/Breadcrumb',
 	component: Breadcrumb,
 	argTypes: {
 		rootLabelText: {
 			control: 'text',
-			defaultValue: 'Document',
+			defaultValue: '',
 			description:
-				'Translated label for the root element of the breadcrumb trail',
+				'Label text for the root element (the first `<li />`) of the breadcrumb trail.',
 		},
 	},
 	decorators: [