[BUG] Weird auto-formatting for lines with a trailing comment

[nmsmith]

Bug description

The following program:

fn main():
    var a = Int(0)
    var b: Int
    b = a^  # xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

is auto-formatted as:

fn main():
    var a = Int(0)
    var b: Int
    b = (
        a^
    )  # xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Whereas if the ^ sigil is removed, or if the initialization is done on the same line as the declaration (var b = a^), the auto-formatter doesn't intervene.

Ideally, in all cases, the formatter will just leave the code alone, because splitting it over multiple lines doesn't aid readability.

This issue isn't specific to the ^ sigil. It also occurs with lines like b = +a and b = a + 1.

System information

MacOS Ventura
Mojo nightly 2024.5.622 (d9dc4c21)