`imports_granularity=One` removes macro imports that share names with modules

#![no_implicit_prelude]
extern crate alloc;

use alloc::boxed;
use alloc::vec;
use alloc::vec::Vec;

fn main() {
    let _: Vec<i32> = vec![];
}

turns into

#![no_implicit_prelude]
extern crate alloc;

use alloc::{
    boxed,
    vec::{self, Vec},
};

fn main() {
    let _: Vec<i32> = vec![];
}

after

$ rustfmt --unstable-features --config imports_granularity=One ./src/main.rs

This is no longer valid rust, as the vec! macro isnt in scope anymore.

tested on latest nightly:

$ rustfmt -V
rustfmt 1.8.0-nightly (d5419f1e97 2025-10-30)
$ rustc -V
rustc 1.93.0-nightly (d5419f1e9 2025-10-30)

Reproduce the issue from the provided src/main.rs example with rustfmt --unstable-features and imports_granularity=One. Trace the import-granularity handling and add a regression test covering a macro and module with the same name. Done means the formatted code still resolves vec! and remains valid Rust.