toc: remove docs home from left navigation (#21528) (#21532)

Author: ti-chi-bot

TOC.md

@@ -1,7 +1,6 @@
 <!-- markdownlint-disable MD007 -->
 <!-- markdownlint-disable MD041 -->
 
-- [Docs Home](https://docs.pingcap.com/)
 - About TiDB
   - [TiDB Introduction](/overview.md)
   - [TiDB 5.4 Release Notes](/releases/release-5.4.0.md)