Add fragment_depth feature (#600)

Add the fragment_depth language feature added in
https://github.com/gpuweb/gpuweb/pull/6299

webgpu.h

diff --git a/webgpu.h b/webgpu.h
index 3831c2c..b5e822b 100644
--- a/webgpu.h
+++ b/webgpu.h
@@ -1256,6 +1256,7 @@
     WGPUWGSLLanguageFeatureName_ImmediateAddressSpace = 0x0000000B,
     WGPUWGSLLanguageFeatureName_BufferView = 0x0000000C,
     WGPUWGSLLanguageFeatureName_SwizzleAssignment = 0x0000000D,
+    WGPUWGSLLanguageFeatureName_FragmentDepth = 0x0000000E,
     WGPUWGSLLanguageFeatureName_Force32 = 0x7FFFFFFF
 } WGPUWGSLLanguageFeatureName WGPU_ENUM_ATTRIBUTE;
 

webgpu.json

diff --git a/webgpu.json b/webgpu.json
index fb2f01c..68feb9a 100644
--- a/webgpu.json
+++ b/webgpu.json
@@ -2441,6 +2441,10 @@
         {
           "doc": "TODO\n",
           "name": "swizzle_assignment"
+        },
+        {
+          "doc": "TODO\n",
+          "name": "fragment_depth"
         }
       ],
       "name": "WGSL_language_feature_name"

webgpu.yml

diff --git a/webgpu.yml b/webgpu.yml
index ad031e1..3dbb967 100644
--- a/webgpu.yml
+++ b/webgpu.yml
@@ -1543,6 +1543,9 @@
       - name: swizzle_assignment
         doc: |
           TODO
+      - name: fragment_depth
+        doc: |
+          TODO
 bitflags:
   - name: buffer_usage
     doc: |