Add algolia search

[keynmol]

Closes #962

To Algolia's credit, adding this was 5 minutes of following instructions and a whole day of CSS. Mostly because layout.html didn't do anything for some reason, so I had to add and remove lots of custom css.

Plus there's duplication of .st pages.

In the end I removed all the custom CSS and decided to make Algolia's base bootstrap theme to work properly first.

Outstanding:

• @eed3si9n to apply for docsearch here: https://docsearch.algolia.com/docs/apply (sorry for picking on you Eugene, not sure what the full list of maintainers looks like :-)

  Given that API key is public, once there's one I'll be able to test this locally without having to merge 🎉

• Some CSS tweaks to match the theme?

• Might be able to add language-localised to pages not in English, if it's worth it? I don't know how DocSearch's indexing works

Here's what it looks now with index pointing at scala-lang.org DocSearch

1. Reference pages
   
2. Langing page
   

[lightbend-cla-validator]

Hi @keynmol,

Thank you for your contribution! We really value the time you've taken to put this together.

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[eed3si9n]

For the record I did apply for DocSearch yesterday. Since it's Thanksgiving weekend, it might take a few days to process?

[keynmol]

Ah yes, you're right. Either way, the wheels are turning and SBT site should be at the top of priority list as it's open source :)

[eed3si9n]

Hello! I got the API key.

<!-- at the end of the HEAD -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.css" />

<!-- at the end of the BODY -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.js"></script>
<script type="text/javascript"> docsearch({
apiKey: 'e47ee877a07ea1c48722f08430d54913',
indexName: 'scala-sbt',
inputSelector: '### REPLACE ME ####',
algoliaOptions: { 'facetFilters': ["lang:$LANG"] },
debug: false // Set debug to true if you want to inspect the dropdown
});
</script>

[eed3si9n]

And configuration is here - https://github.com/algolia/docsearch-configs/blob/master/configs/scala-sbt.json

[keynmol]

Yohoo!

Let me update the PR and see what sort of results we get.

I can also push the locally generated version termporarily to http://surge.sh so that you can have a play around

[keynmol]

Perhaps the indexing hasn't happened yet - I've pushed the site with new configs here: http://scala-sbt.surge.sh/index.html

I can see requests going to algolia okay but the response doesn't contain any results.

I'll see if the regex in their sbt config is correct.

[keynmol]

A-ha, the regex is indeed incorrect. It collects everything after /docs into a lang facet filter.

Which means if I remove the facet filter the search should work.

[keynmol]

We're live! (I pushed the change to the the http://scala-sbt.surge.sh/1.x/docs/ as well)

But lack of facet does mean that visitors will learn a language or two :)

[eed3si9n]

Thanks!