Add Notepad to the list of supporting text editors.

[schuelermine]

The default Windows notepad.exe displays ligatures by default, even when the ligature has a different width.

[i-tu]

I decided to remove the compatibility list as it is probably out of date. Ligatures have become pretty mainstream now too. The Fira Code repository maintains a list that is the probably the best one available: https://github.com/tonsky/FiraCode