Change from LunrJs to MinisearchJs for client-side search

[Hetarth02]

This PR aims to close Issue #2141.

[mortenpi]

Something I noticed while testing is that it likes to repeat page headings a lot:

The lunr based approach doesn't do that:

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One other note: the PR has also a lot of non-substantial formatting changes. While I don't disagree with the changes, it's generally a good idea to make the formatting changes independently. In this case, though, it's a little less important -- we're kinda replacing the whole search.js anyway. But it is a little tricky to see right now how the implementations differ, and where they're the same.

What formatter are you using though? We should probably add a config file and a CI job to format all the JS and CSS at least. There is a suggestion to use eslint: #2072. Separately, we should also apply JuliaFormatter to the Julia code too, but let's cross that bridge a bit later.

[Hetarth02]

@mortenpi I have fixed the duplication issue.

Additionally, I have updated the search result UI to provide better context for the results like displaying not only title but the matched string(if found) and the category badge too.

The new UI looks like this,

[mortenpi]

Awesome! Mostly just a bit of bikeshedding. The main thing would be moving the search layout stuff into a shared SCSS file, to avoid duplication, but then I'd pretty much be happy to merge I think.

[Hetarth02]

Alright, will clean up the code as suggested.

[mortenpi]

This LGTM, thank you @Hetarth02! I need to get the Prettier workflow working properly, so I'll hold off on merging until that passes.