Syntax error on JavaScript for specific number syntax

[GearsDatapacks]

In Gleam, numbers are allowed to look something like this: 0x_abcd, whereas in JavaScript, the 0x prefix (along with 0b and 0o) cannot be followed immediately by an underscore.
Since the Gleam compiler currently performs no transformation on numbers when compiling to JavaScript, this causes a syntax error.
This is not a problem on Erlang as the compiler already has to transform 0x in 16#, and the invalid syntax is eliminated in the process.
We can probably just check for 0b_, 0x_ and 0o_ at the start of numbers and remove the underscore in that case.