Make WGPUSupportedFeatures non-extensible

This was the original intent:
webgpu-native#252 (comment)
I just did it wrong in my PR (webgpu-native#348).

webgpu.yml

@@ -2644,7 +2644,7 @@ structs:
   - name: supported_features
     doc: |
       TODO
-    type: base_out
+    type: standalone
     free_members: true
     members:
       - name: features
@@ -3212,7 +3212,6 @@ objects:
             Return @ref WGPUStatus_Error (and leaves `features` uninitialized) if:
 
             - `features` has an invalid struct chain.
-          type: enum.status
         args:
           - name: features
             doc: |
@@ -3918,7 +3917,6 @@ objects:
             Return @ref WGPUStatus_Error (and leaves `features` uninitialized) if:
 
             - `features` has an invalid struct chain.
-          type: enum.status
         args:
           - name: features
             doc: |