Real-time highlighting of the search results

[yousfiSaad]

Description

This is an implementation of the Incremental search and highlights features.
Issues talking about this feature are : #3469 , #591 , #3100

[gdh1995]

As said in #3469 (comment), this PR creates new DOM elements to add styles to matched text, but this behavior may break some pages .

I suggest that we may use element.getBoundingClientRect() and create many <div style="left:...;top:...;width:...;height:..."> to show bounding boxes (without background color), like what Ctrl+Shift+J/K do in my Vimium C (https://github.com/gdh1995/vimium-c).

[chrisgrieser]

I'd love to have the feature merged into vimium 🙏

[MathiasSven]

As others have expressed, even if the implementation as it currently is might break in some pages, the benefits of the feature might outweigh the potential issues, what would be the harm in having this as an optional experimental feature under the advanced options with a disclamer?