An error during validation of inbound links breaks the `docs-build` check on the `elasticsearch/9.1` branch

[vishaangelova]

While backporting a PR on the 9.1 branch of the elasticsearch repo, I noticed that the docs-build check on the PR breaks because of a missing anchor (unrelated to the changes in the PR).

The missing anchor was added in PR #133831 on the main branch of the elasticsearch repo, but the PR wasn't backported to the 9.0 and 9.1 branches. The only link I found to the missing anchor is in the docs-content repo in troubleshoot/elasticsearch/file-based-recovery.md.

Does the build break because it tries to validate the links on the main branch of docs-content against the docs on the elasticsearch/9.1 branch?

The backport was auto-merged regardless of the error thanks to the auto-merge-without-approval label added by the backport tool, and the error itself doesn't affect the docs site because we build the 9.x docs from the elasticsearch/main branch.

However, if we're going to have this check on the elasticsearch/9.1 branch, should we fix the error by backporting the PR that introduced the missing anchor?

(FYI: the docs-build check did not run on the backport for the 9.0 branch, so there was no error there.)