naga: Fix reference to serde feature.

naga doesn't have a `serde` feature, instead having separate
`serialize` and `deserialize` features, so things that want to
modify the serde handling must check for either of those, not
for `serde` itself.

naga/src/back/msl/mod.rs

@@ -295,7 +295,10 @@ pub enum VertexFormat {
     /// Four signed ints (i32). `vec4<i32>` in shaders.
     Sint32x4 = 29,
     /// Three unsigned 10-bit integers and one 2-bit integer, packed into a 32-bit integer (u32). [0, 1024] converted to float [0, 1] `vec4<f32>` in shaders.
-    #[cfg_attr(feature = "serde", serde(rename = "unorm10-10-10-2"))]
+    #[cfg_attr(
+        any(feature = "serialize", feature = "deserialize"),
+        serde(rename = "unorm10-10-10-2")
+    )]
     Unorm10_10_10_2 = 34,
 }