State that webgpu.h has the same behavior as the JS spec (#452)

Author: kainino0x

gen/cheader.tmpl

@@ -9,6 +9,12 @@
  *
  * This is the home of WebGPU C API specification. We define here the standard
  * `webgpu.h` header that all implementations should provide.
+ *
+ * For all details where behavior is not otherwise specified, `webgpu.h` has
+ * the same behavior as the WebGPU specification for JavaScript on the Web.
+ * The WebIDL-based Web specification is mapped into C as faithfully (and
+ * bidirectionally) as practical/possible.
+ * The working draft of WebGPU can be found at <https://www.w3.org/TR/webgpu/>.
  */
 
 #ifndef {{.HeaderName | ConstantCase}}_H_

webgpu.h

@@ -13,6 +13,12 @@
  *
  * This is the home of WebGPU C API specification. We define here the standard
  * `webgpu.h` header that all implementations should provide.
+ *
+ * For all details where behavior is not otherwise specified, `webgpu.h` has
+ * the same behavior as the WebGPU specification for JavaScript on the Web.
+ * The WebIDL-based Web specification is mapped into C as faithfully (and
+ * bidirectionally) as practical/possible.
+ * The working draft of WebGPU can be found at <https://www.w3.org/TR/webgpu/>.
  */
 
 #ifndef WEBGPU_H_