added comment

Author: didoo

packages/components/src/components/hds/layout/flex/index.hbs

@@ -2,6 +2,10 @@
   Copyright (c) HashiCorp, Inc.
   SPDX-License-Identifier: MPL-2.0
 }}
+{{!
+  Dynamically generating an HTML tag in Ember creates a dynamic component class (with the corresponding tagName), while rendering
+  a plain HTML elements requires less computing cycles for Ember (you will notice it doesn't add the `ember-view` class to it).
+}}
 {{#if (eq this.componentTag "div")}}
   <div class={{this.classNames}} ...attributes>{{yield (hash Item=(component "hds/layout/flex/item"))}}</div>
 {{else}}