doc: update copyright

Author: Flash-LHR

README.md

@@ -22,6 +22,6 @@ Considering that tRPC-Go provides a variety of plugins for naming routing, monit
 | mysql | Wraps the open-source database [MySQL Driver](https://github.com/go-sql-driver/mysql) |
 | timer | Local/distributed timer functionality |
 
-#@ Copyright
+## Copyright
 
 The copyright notice pertaining to the Tencent code in this repo was previously in the name of “THL A29 Limited.”  That entity has now been de-registered.  You should treat all previously distributed copies of the code as if the copyright notice was in the name of “Tencent.”