SystemSet does not take SystemTypeIdLabel like ParallelSystemDescriptor

[CGMossa]

Mixing labels with SystemSet does not work, but it does for Systems. I've been told it is because the changes
to ParallelSystemDescriptor wasn't applied to SystemSet.

Example

use bevy_app::prelude::*;
use bevy_ecs::prelude::*;

#[allow(dead_code)]
fn some_system() {}

#[allow(dead_code)]
fn another_system() {}

#[allow(dead_code)]
fn dummy_system() {}

fn main() {
    let mut app = App::new();

    app.add_system(dummy_system.label("dummy system"));
    app.add_system(another_system);
    // fails to compile:
    app.add_system_set(
        SystemSet::new()
            .with_system(some_system)
            .after(another_system)
            .after("dummy system"),
    );

    app.run();
}

error[E0277]: the trait bound `fn() {another_system}: SystemLabel` is not satisfied
   --> examples\system_labels_and_custom_labels.rs:22:16
    |
22  |         .after(another_system)
    |          ----- ^^^^^^^^^^^^^^ the trait `SystemLabel` is not implemented for `fn() {another_system}`
    |          |
    |          required by a bound introduced by this call
    |
note: required by a bound in `bevy_ecs::schedule::SystemSet::after`
   --> C:\Users\Tyler\.cargo\git\checkouts\bevy-f7ffde730c324c74\26c3b20\crates\bevy_ecs\src\schedule\system_set.rs:104:40
    |
104 |     pub fn after(mut self, label: impl SystemLabel) -> Self {
    |                                        ^^^^^^^^^^^ required by this bound in `bevy_ecs::schedule::SystemSet::after`

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