safe-ts redirects to wrong page

[choudharypankaj]

Change Request

Please answer the following questions before submitting your issue. Thanks!

1. Describe what you find is inappropriate or missing in the existing docs.
   safe-ts link redirects to wrong page

2. Describe your suggestion or addition.
   It should redirect to:
   https://docs.pingcap.com/tidb/stable/troubleshoot-stale-read/#what-is-safe-ts

3. Provide some reference materials (such as documents and websites) if you could.