Fix link in field type index

[kolchfa-aws]

Fix link in field type index

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[opensearch-trigger-bot]

The backport to 2.5 failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/backport-2.5 2.5
# Navigate to the new working tree
pushd ../.worktrees/backport-2.5
# Create a new branch
git switch --create backport/backport-4463-to-2.5
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c8e061bcca154567815871b6477c13fbdf266299
# Push it to GitHub
git push --set-upstream origin backport/backport-4463-to-2.5
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/backport-2.5

Then, create a pull request where the base branch is 2.5 and the compare/head branch is backport/backport-4463-to-2.5.