add dxc error message formatting

[Davidster]

Checklist

• Run cargo clippy.
• Run RUSTFLAGS=--cfg=web_sys_unstable_apis cargo clippy --target wasm32-unknown-unknown if applicable.
• Add change to CHANGELOG.md. See simple instructions inside file.

Connections
n/a

Description
Currently, error messages from dxc are not included in the error messages reported by wgpu. Before this change, error messages would look like this:

[2023-04-01T19:51:14Z ERROR wgpu::backend::direct] Handling wgpu errors as fatal by default
thread 'main' panicked at 'wgpu error: Validation Error

Caused by:
    In Device::create_render_pipeline
      note: label = `iced_wgpu::quad pipeline`
    Internal error in VERTEX shader: DXC compile error: DxcOperationResult { inner: ComPtr { ptr: 0x1c754cd23c0 } }

', wgpu\src\backend\direct.rs:3016:5

After this change, they look like this:

[2023-04-01T19:49:53Z ERROR wgpu::backend::direct] Handling wgpu errors as fatal by default
thread 'main' panicked at 'wgpu error: Validation Error

Caused by:
    In Device::create_render_pipeline
      note: label = `iced_wgpu::quad pipeline`
    Internal error in VERTEX shader: DXC compile error: "error: error reading 'iced_wgpu::quad::shader'\n\0"

', wgpu\src\backend\direct.rs:3016:5

Testing
The change can be tested by triggering a dxc compile error, which can be triggered by adding a colon in the name of the shader module:

wgpu::ShaderModuleDescriptor {
    label: Some(":"),
    ..
}

[Elabajaba]

LGTM.

I don't love the closure, but that's just nitpicking over style.