wgpu-hal: Expose vulkan::PhysicalDeviceFeatures

[afishhh]

Connections
Fixes #7681

Description
PhysicalDeviceFeatures is currently accessible through vulkan::Adapter::physical_device_features which is a public function. This structure seems required to be able to tell what Vulkan device features wgpu needs so it would be nice if it was accessible externally as otherwise it's impossible to create a wgpu Device from Vulkan objects safely.

Re-exporting the type is the workaround I used just to get what I was doing to succeed, alternatively the whole adapter module could be made public or glob re-exported, this would also expose PhysicalDeviceProperties which appears to have the same issue.

Testing
Call Adapter::physical_device_features, notice that you can't name this type due to it being private.

Squash or Rebase?
Any

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.

[afishhh]

Ah clippy complains because the documentation links to private items now, not sure what to do about this since the function it links to does indeed seem pretty internal.