`assert_is_empty` suggests unnecessary cast for `Vec<_>`

Summary

assert_is_empty could avoid suggesting an unnecessary cast when the asserted value is a Vec<_>. The suggested empty array can be written directly as [].

Reproducer

Code:

pub fn issue17673(v: Vec<u8>) {
    assert!(v.is_empty());
}

Current output:

pub fn issue17673(v: Vec<u8>) {
    assert_eq!(v, [] as [u8; 0]);
}

Desired output:

pub fn issue17673(v: Vec<u8>) {
    assert_eq!(v, []);
}

https://rust.godbolt.org/z/MEnr8bGMd

Version

clippy 0.1.100 (5db7f4be8a 2026-09-01)

Start with the assert_is_empty lint and reproduce the issue using the Rust example in the report. Find the lint's implementation and existing tests, then update the suggestion so Vec<_> produces [] without a cast; done means the desired output is emitted and the relevant tests pass.