Avoid multiple results for the same keyword

Hmm my patch from #8 doesn't apply anymore, but I'm not sure it's needed now. I tried testing a few super generic words, such as "the", and didn't see any duplicates. Perhaps we can just mark this as needs review without the patch?

@mpp, can you confirm this has been fixed in the meantime?

The issue is not reproducible.
I have tested the feature with Drupal 10.2.7 & search_api_autocompleteVersion: 8.x-1.8 version.
Adding few screenshots for help.