Filter duplicate index pages from search results

[marc1404]

How to categorize this PR?

/kind bug

What this PR does / why we need it:

Historically our source documentation files are using _index.md as the default name for index pages.
Since migrating from Hugo to VitePress, we're using a post-processing step (post-processing/part-index.js) to copy and rename all _index.md files to index.md.
This leads to duplicate search results since both _index.md and index.md are indexed by MiniSearch.

Example for the root cause of this issue in the local hugo folder created by Docforge:

Example test for filtered search results locally:

Which issue(s) this PR fixes:
Fixes #842

Special notes for your reviewer:

/cc @n-boshnakov @klocke-io

[marc1404]

ℹ️ Fix for the failing PR preview workflow:

• Use correct Make target in PR preview workflow #844

[marc1404]

/ok-to-test

[github-actions]

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[marc1404]

ping @n-boshnakov @klocke-io :)

[gardener-robot]

@klocke-io, @n-boshnakov You have pull request review open invite, please check

[klocke-io]

/lgtm

[gardener-prow]

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[gardener-prow]

LGTM label has been added.

Details

Git tree hash: 291d3d07d71687228ca9536f875af053237f9153