docs - Not valid link to icons
This [link](https://apps.gnome.org/app/org.gnome.design.IconLibrary) is no longer valid in:
https://github.com/can-lehmann/owlkettle/blob/8028418f8e5d0b9fbd90def62b11a3810ddf4565/docs/recommended_tools.md?plain=1#L16