feat(templates): add data access explanation

templates/basic/src/components/my-hello-world.js

@@ -13,6 +13,11 @@ class HelloWorld extends WebComponent {
   }
 
   get template() {
+    /**
+     * any attribute/property in kebab-case...
+     * can be accessed via its camelCase counterpart
+     * example: data-name prop is accessible as this.dataName
+     */
     return `<button style="cursor:pointer">Hello ${this.dataName}!</button>`;
   }
 }