bug: AST to_string() pretty-printing does not indent properly

[thetayloredman]

Before we begin...

• I have updated the Zirco toolchain to the latest version
• I have searched the issue tracker for duplicates

What happened?

Blocks like if within the AST pretty-print to string do not get indented or given newlines like they do in the TAST.

What version of Zirco are you running?

zrc version 0.1.0 (4b07b66, not tainted) built for x86_64-unknown-linux-gnu on 2023-10-18T08:46:15-07:00 (debug mode)
rustc 1.70.0 (90c541806 2023-05-31) (stable-x86_64-unknown-linux-gnu on linux-x86_64)
cargo 1.70.0 (ec8a8a0ca 2023-04-25)

How can this bug be reproduced?

After #60, run zrc --emit ast on the following:

fn main() -> i32 {
    if (2 + 2 == 5) {
        return 1;
    } else {
        return 0;
    }
}

What behavior did you expect?

fn main() -> i32 {
    if ((((2) + (2)) == (5))) {
        return (1);
    } else {
        return (0);
    }
}

What actually happened?

fn main() -> i32 {
    if ((((2) + (2)) == (5))) {return (1);} else {return (0);}
}

Other Context

It may be helpful to indent all lines except the first by a certain indentation level in all blocks?