rustfmt formats a macro when it should not

rustfmt is formatting - changing indentation - inside a macro, in what is not valid Rust code.

In the code below, if you change the indentation inside the proptest! macro, rustfmt will change it back to the way it is currently, when it should not. Repo with the repro.

#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Item {
    pub first_long_name_a: u16,
    pub item_count: u16,
    pub area: u16,
    pub address: u16,
}

#[cfg(test)]
mod tests {
    use proptest::prelude::*;

    use super::Item;

    proptest! {
               #[test]
               fn read_item_chars(s in "\\PC*") {
                   let pi = Item{
    first_long_name_a: 0,item_count: 0,area: 0,address: 0,};
               }
           }
}

Tested on both 1.82 and nightly.

$ cargo fmt --version
rustfmt 1.7.1-stable (f6e511e 2024-10-15)
$ cargo +nightly fmt --version
rustfmt 1.8.0-nightly (33c245b9e9 2024-12-10)

Start by reproducing the behavior in the linked proptest repository and running the supplied stable and nightly cargo fmt versions. Done means rustfmt leaves indentation inside the proptest! macro unchanged when that content is not valid Rust code.