Fira ligatures incorrectly display 'x'

### What did you expect to happen?

FIra ligatures have support for hex ligature, which means that 0x10 for example will make the 'x' centered and smaller.

### What actually happened?

When i write x in code without the 0 prefix, the x is ligatured, whereas when i write it with the 0 prefix it isn't.

### Describe your attempts to resolve the issue

_No response_

### Steps to reproduce

I have enabled the ui: (ligatures +fira) and use the Fira Code font

### System Information

https://pastebin.com/9FxCwyZ5