tint/ast: Generate interpolate_attribute.[h|cc]

Emits all the enum info from the single-source-of-truth `intrinsics.def` file

Change-Id: Ie9deba9e64927945133027cf243777944119ea41
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/105327
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/ast/builtin_value.h b/src/tint/ast/builtin_value.h
index eb45b39..f7dd660 100644
--- a/src/tint/ast/builtin_value.h
+++ b/src/tint/ast/builtin_value.h
@@ -27,7 +27,7 @@
 
 namespace tint::ast {
 
-/// Storage class of a given pointer.
+/// Builtin value defined with `@builtin(<name>)`.
 enum class BuiltinValue {
     kInvalid,
     kFragDepth,