How to properly implement custom tasklist icons

[Andre601]

This was originally posted in facelessuser/pymdown-extensions#1256
See for full context

I currently try to alter the styling of the icons used for the tasklist extension of pymdown, but struggle with getting it to work.
I first tried to just add some CSS to as extra_css to override, which failed. Then I tried to extend the theme to override the settings by first adding SVG icons from fontawesome into theme/.icons/fontawesome/regular/square.svg and theme/.icons/fontawesome/solid/check-square.svg before adding theme/assets/stylesheets/extensions/pymdownx/_tasklist.scss to override the default one with its icons.
theme is the folder used for theme extension and is also set as custom_dir in the mkdocs.yml file.

But even with the above steps done and with clearing the cache for deploy-preview is the page still using the original stylesheets without any changes applied.

My goal is to have checkboxes similar to those of GitHub, which I want to emulate using check-square and square from FontAwesome.

Also, I tried it with both custom_checkbox enabled and disabled. Enabled shows the circles and disabled shows nothing.

Any help in solving this would be appreciated.

[Andre601]

I found a solution, see #2361