🔧 chore: use custom highlights api for text highlighting

[lcottercertinia]

🔧 Chore Description

What needs to be done?

We currently create extra span elements for the highlighting which modifies the dom. This means we have to modify the dom again to do an accurate search.
The custom highlights api does not modify the dom!

https://developer.mozilla.org/en-US/docs/Web/API/CSS_Custom_Highlight_API