Support underscores in numeric literals

[cburgdorf]

Abstract

We should support underscores _ in numeric literals so that 1000000000000000000 can be written in the more readable form of 1_000_000_000_000_000_000.

Motivation

Fe is intended to be used in smart contract development and variables and constants holding large numerals is a very well expected normal use case. Especially since many variables are going to represent Wei and e.g. 1_000_000_000_000_000_000 Wei represent 1 Ether.

[plv]

Hi, does this still need doing? Happy to take it on.

[cburgdorf]

@plv yes, feel free to take it!

[voith]

@plv are you still working on this? If not can I take this up?

[plv]

@voith Sorry for the late response -- I never got around to this. Feel free to take it :)

[Jake-Steck]

@plv Hi, does this still need help? I am here if so.

[cburgdorf]

@Jake-Steck it doesn't seem that anyone is currently actively working on it so feel free to make it yours :)

[voith]

@Jake-Steck I never got started on this. So feel free to take it.