Fix guess renamed macro braces

[A4-Tacks]

Input (bar!):

/// foo![]
#[macro_export]
macro_rules! foo { () => {}; }
pub use crate::foo as bar;

fn main() {
    $0
}

Old output:

/// foo![]
#[macro_export]
macro_rules! foo { () => {}; }
pub use crate::foo as bar;

fn main() {
    bar!($0)
}

This PR output:

/// foo![]
#[macro_export]
macro_rules! foo { () => {}; }
pub use crate::foo as bar;

fn main() {
    bar![$0]
}

[ChayimFriedman2]

I don't think this needs to be in the docs. This probably deserves a #[rust_analyzer::] attribute.

[Veykril]

I think we do want to keep the doc trick here as a good heuristic, but a rust-analyzer attribute would be nice to have for this as well