chore: fix broken links (backport #2511)

[mergify]

This is an automatic backport of pull request #2511 done by Mergify.
Cherry-pick of 4c45212 has failed:

On branch mergify/bp/release/v2.3.x/pr-2511
Your branch is up to date with 'origin/release/v2.3.x'.

You are currently cherry-picking commit 4c45212.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   .github/PULL_REQUEST_TEMPLATE.md
	modified:   docs/DOCS_README.md
	modified:   docs/ibc/apps.md
	modified:   docs/ibc/integration.md
	modified:   docs/ibc/overview.md
	modified:   docs/ibc/relayer.md

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/ibc/apps/apps.md
	deleted by us:   docs/middleware/ics29-fee/fee-distribution.md
	both modified:   modules/apps/transfer/spec/06_metrics.md

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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