Explorer: added styling for nodes at root

 of workspace

Added a tabbing for the child nodes of a root, to have a visual
 difference and avoid confusion

packages/filesystem/src/browser/file-tree/file-tree-widget.tsx

@@ -316,7 +316,7 @@ export class FileTreeWidget extends CompressedTreeWidget {
     }
 
     protected override getDepthPadding(depth: number): number {
-        // add additional extra depth so file nodes are rendered with padding in relation to the top level root node (to properly differentiate items in the tree)
+        // add additional depth so file nodes are rendered with padding in relation to the top level root node.
         return (depth + 1) * this.props.leftPadding;
     }
 }