fix: preserve newlines between comments when formatting statements

[asterite]

Description

Problem

Just a small formatter issue I found while trying to reduce some code by commenting it.

Summary

Previously this code:

fn main() {
    let a = 1;

    // let x = 1;

    // let y = 2;
}

was formatted to this one:

fn main() {
    let a = 1;

    // let x = 1;
    // let y = 2;
}

With this PR the newline between comments is preserved.

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[jfecher]

I somewhat prefer the version with the newline removed in this case but it looks like rustfmt also preserves the newline