Update TiDB Docs archived title for better SEO

[likidu]

PingCAP Docs -> TiDB Archived Docs

[lilin90]

2024-11-05 update:

The "TiDB Archived Docs" shows after the page title:

However, when your hover your mouse over the link, you can see the doc link of the "stable" version in the lower-left corner. In fact, if you click the link of the result, it jumps to the archived page https://docs-archive.pingcap.com/tidb/v4.0/loader-overview. This is weird. I've requested @shhdgit to help resolve this issue.