Update docs for Backend and implement std::fmt::Display

CHANGELOG.md

@@ -94,7 +94,7 @@ Bottom level categories:
   - As with other instance flags, this flag can be changed in calls to `InstanceFlags::with_env` with the new `WGPU_GPU_BASED_VALIDATION` environment variable.
 
   By @ErichDonGubler in [#5046](https://github.com/gfx-rs/wgpu/pull/5046).
-
+- `wgpu::Backend` now implements `std::fmt::Display` instead of providing a `to_str` method
 
 ### Bug Fixes
 

tests/src/image.rs

@@ -183,7 +183,7 @@ pub async fn compare_image_output(
     let file_stem = reference_path.file_stem().unwrap().to_string_lossy();
     let renderer = format!(
         "{}-{}-{}",
-        adapter_info.backend.to_str(),
+        adapter_info.backend,
         sanitize_for_path(&adapter_info.name),
         sanitize_for_path(&adapter_info.driver)
     );

wgpu-types/src/lib.rs

@@ -98,21 +98,21 @@ pub const QUERY_SIZE: u32 = 8;
 pub enum Backend {
     /// Dummy backend, used for testing.
     Empty = 0,
-    /// Vulkan API
+    /// Vulkan API (Windows, Linux, Android, MacOS via `vulkan-portability`/MoltenVK)
     Vulkan = 1,
     /// Metal API (Apple platforms)
     Metal = 2,
     /// Direct3D-12 (Windows)
     Dx12 = 3,
-    /// OpenGL ES-3 (Linux, Android)
+    /// OpenGL ES-3 (Linux, Android, WebGL, Windows, MacOS via Angle)
     Gl = 4,
     /// WebGPU in the browser
     BrowserWebGpu = 5,
 }
 
 impl Backend {
     /// Returns the string name of the backend.
-    pub fn to_str(self) -> &'static str {
+    pub const fn to_str(self) -> &'static str {
         match self {
             Backend::Empty => "empty",
             Backend::Vulkan => "vulkan",
@@ -124,6 +124,12 @@ impl Backend {
     }
 }
 
+impl std::fmt::Display for Backend {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.to_str())
+    }
+}
+
 /// Power Preference when choosing a physical adapter.
 ///
 /// Corresponds to [WebGPU `GPUPowerPreference`](