configurations.md and backup_and_migration.md cross-linked each other
via /migration#... and /configurations#s3-tigris. These host-absolute
paths match no route on the docs site (real pages live under
/administrator/...) and 404 on GitHub. Point them at the sibling
markdown files so both Docusaurus and GitHub can resolve them; the
existing anchors are preserved.
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Co-authored-by: jindou <jindou@local>
Co-authored-by: Jin Hai <haijin.chn@gmail.com>