Pouya Kary ✨

Spread operator added (referencing JS as always)

Added the optionality keyword:

Fixed the problem with nested generics 

@DanTup I actually can I guess, since every different atomic change has been a commit. So even the formatting is a commit. I don't know if you have seen the...

Okay then let me move to that repo and recommit these there with the proper style.

A new full grammar for the `get` / `set` pattern so that the next token after them are marked as a function definition (as what they are) 


So I didn't know that the get could be async and even generator :) how cool is that :) anyhow, that is fixed:

Extension definition grammar is added: --- 

@DanTup sorry that I haven't had a chance to work on the tests. Still working on the grammar as I learn the language