[Docs] Add TOC to Button.md

PiperOrigin-RevId: 738491983

Author: dsn5ft

docs/components/Button.md

@@ -28,6 +28,8 @@ and make choices, with a single tap.
 *   [Icon button](#icon-button)
 *   [Theming](#theming-buttons)
 
+[TOC]
+
 ## Design and API Documentation
 
 *   [Google Material3 Spec](https://material.io/components/buttons/overview)