fix link to custom user page

Author: eoghanteamblue

docs/hypernode-platform/mysql/how-to-use-mysql-on-hypernode.md

@@ -321,7 +321,7 @@ Upgrading to MySQL 8.4 is only supported from MySQL 8.0.
 If you are not yet on MySQL 8.0, first follow the steps above to upgrade to 8.0.
 
 Before upgrading, ensure all MySQL users are using supported authentication plugins (for example `caching_sha2_password`).  
-See [Changing the Authentication Plugin for a MySQL User](#changing-the-authentication-plugin-for-a-mysql-user) for details.
+See [Changing the Authentication Plugin for a Custom MySQL User](#changing-the-authentication-plugin-for-a-custom-mysql-user) for details.
 
 Once ready, run the following command: