Add missing semicolon to satisfy clippy

[mfreeborn]

Just a trivial PR

[mfreeborn]

The other one I'm seeing is

warning: use of `default` to create a unit struct
   --> wgpu/src/layer.rs:386:21
    |
386 |             images: image::Batch::default(),
    |                     ^^^^^^^^^^^^-----------
    |                                 |
    |                                 help: remove this call to `default`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.91.0/index.html#default_constructed_unit_structs
    = note: `#[warn(clippy::default_constructed_unit_structs)]` on by default

But image::Batch is defined as pub type Batch = Vec<Image>, so I don't understand how that works...

[mfreeborn]

(I admit I thought a bit more would go in this PR when I created it; I realise it's a bit pointless on it's own and you'll just sort out clippy and whatever yourself as and when required)