Patch Jetbrains mono to not use ligatures for `==` and `__`

[aminya]

I love ligatured fonts specially Jetbrains mono, but it is hard for me to detect == and __ when I am using a ligatured font. Can you make a patch that contains all the ligatures but these two?

When I use Jetbrains mono without ligatures it looks very good:

[gaplo917]

@aminya As this is an opinionated request. I would rather provide a guide for you to build your custom font.

1. Please follow the Getting Start to ready for patching your custom font.

2. As the current script is referencing fonts/fira/showcases/**/showcases.txt file, just remove the ligatures you don't want in the showcases.txt.

3. Follow the Manual Build via docker to create your custom build!

4. You will found the fonts in ./fonts/output