Incorporate new ligatures in Fira Code v2, v3, v4 and v5

[wopian]

Fira Code v3 was released last month and v4 this week. v2 & v3 includes a large number of new coding ligatures (from the looks of things the ligatures from Fira Code seem to be before v2).

Releases show the added ligatures and what they look like:
https://github.com/tonsky/FiraCode/releases/tag/4
https://github.com/tonsky/FiraCode/releases/tag/3
https://github.com/tonsky/FiraCode/releases/tag/2

v4 features infinite arrow combinations instead of tens of individual ligatures:

[aaronbell]

Thanks! We'll definitely look into these.

[wopian]

v5 has been released with a few more ligatures

https://github.com/tonsky/FiraCode/releases/tag/5

[subnut]

@aaronbell Any ETA? Anybody working on this yet?

[aaronbell]

Hi. No, we haven't started on this yet. Sorry! We're figuring out next steps for the font :).

[wopian]

Thank you 🎉