Unnecessary Vec/VecDeque reserve lint

[leonardo-m]

What it does

Inspired by:
rust-lang/rust#97922

In a basic case like this Clippy could suggest to remove the call to reserve() because it's unnecessary:

Lint Name

unnecessary_reserve

Category

pedantic

Advantage

No response

Drawbacks

No response

Example

fn test1(v: &mut Vec<u32>, b: &[u32]) {
    v.reserve(b.len());
    v.extend(b);
}

The same for VecDeque.

[kyoto7250]

@rustbot claim

[xFrednet]

#9073 is the start of an implementation. The PR was closed due to inactivity. It might be a good reference point, if someone else wants to give this a go :)

[chansuke]

@rustbot claim

[jonboh]

@chansuke do you mind if I take over this?

[xFrednet]

Since there hasn't been any activity since the start of this year, it's safe to assume that you can have this issue. I'll assign you to it 👍