lang: const array size not supported in instruction data

[skrrb]

the following mwe

use anchor_lang::prelude::*;

declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");

const MAX_SIZE: usize = 5;

#[program]
pub mod tst {
    use super::*;

    pub fn initialize(_ctx: Context<Initialize>, _data: [u8; MAX_SIZE]) -> Result<()> {
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize {}

throws

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ParseIntError { kind: InvalidDigit }', lang/syn/src/idl/mod.rs:202:76                                       
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

related to #968 and #1485