1) Update it to v1.0.8
2) Include jekyll-search where it's used only

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Closes #17319 by merging it.

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And link to a relevant blog post w/ more info.
Refs #16966
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.visible-xs(-block) => .hidden-sm-up

Fixes #17263.
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Refs #17237
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I found non working anchors and some naming in consistency. I hope I fixed well. Have a nice day.

/cc @cvrebert

After v4.0.0 stable gets released, as existing translations get updated or completely new v4 translations get created, we can start adding entries back to the list.

http://v4.bootcss.com

Fixes grammatical erratum from cf7819d8