Please provide a variation with ligatures of Fira Code style

[Discussions](https://github.com/adobe-fonts/source-code-pro/issues/96) on ligatures can date back to 6 years ago, where some users were support for ligatures while others were against, thinking that ligatures may harm clarity. Then, 6 years passed and nothing happened. However, are we really unable to make both sides satisfied? In addition, there are worries that one symbol in this programming language may mean something different in that one, for example, `<=`. However, encountering difficulties is at least better than daring not try at all. Based on these questions, I came up with an idea to design a ligaturized variation, hoping to solve this problem.

**EDIT: I totally disagree with the idea that users who want ligatures can use Hasklig. I think that I should emphasize that despite the fact that Hasklig does has ligatures, it is *specifically* designed for Haskell, in which one symbol may mean something different from that in C and some other languages (e.g. `/=`). For a non-Haskell programmer, it's something bad to see a ligature that contradicts its original meaning, for it only leads to confusion, which goes against the original purpose of coding ligatures to improve the readability of code and reduce the workload of brains. Moreover, Hasklig is still using the old source code. That's why I'm proposing of providing ligatures suitable for most languages instead of just one language.**