Created by: voltaek
@XhmikosR Here is the backport you requested in #32512.
This makes changes similar to those made to the v5 docs to update and clarify the Sass compiler used and the minimum rounding precision we recommend with it. The details added are linked to from several places now instead of bits of the info being spread throughout the docs.
I added some notes about Node Sass being deprecated and how Dart Sass should be a mostly drop in replacement if the user would need support for newer Sass features or CSS standards. It's still made clear that we build Bootstrap v4 with Node Sass, so I think this is a good balance of telling them it's still alright to compile with it while also giving them options if they need newer features.