wgsl: Replace [[decoration]] with @decoration

Deprecate the old syntax. Migrate everything to the new syntax.

Bug: tint:1382
Change-Id: Ide12b2e927b17dc93b9714c7049090864cc568d3
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/77260
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: David Neto <dneto@google.com>
diff --git a/src/resolver/storage_class_validation_test.cc b/src/resolver/storage_class_validation_test.cc
index 5d922c2..9965e08 100644
--- a/src/resolver/storage_class_validation_test.cc
+++ b/src/resolver/storage_class_validation_test.cc
@@ -226,7 +226,7 @@
 
 TEST_F(ResolverStorageClassValidationTest, UniformBuffer_Struct_Runtime) {
   // [[block]] struct S { m:  array<f32>; };
-  // [[group(0), binding(0)]] var<uniform, > svar : S;
+  // @group(0) @binding(0) var<uniform, > svar : S;
 
   auto* s = Structure(Source{{12, 34}}, "S", {Member("m", ty.array<i32>())},
                       {create<ast::StructBlockDecoration>()});