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/test/array/assign_to_workgroup_var.wgsl b/test/array/assign_to_workgroup_var.wgsl
index 225f2f2..9fb94eb 100644
--- a/test/array/assign_to_workgroup_var.wgsl
+++ b/test/array/assign_to_workgroup_var.wgsl
@@ -1,4 +1,4 @@
-type ArrayType = [[stride(16)]] array<i32, 4>;
+type ArrayType = @stride(16) array<i32, 4>;
 
 struct S {
   arr : ArrayType;
@@ -6,8 +6,8 @@
 
 var<private> src_private : ArrayType;
 var<workgroup> src_workgroup : ArrayType;
-[[group(0), binding(0)]] var<uniform> src_uniform : S;
-[[group(0), binding(1)]] var<storage, read_write> src_storage : S;
+@group(0) @binding(0) var<uniform> src_uniform : S;
+@group(0) @binding(1) var<storage, read_write> src_storage : S;
 
 var<workgroup> dst : ArrayType;
 var<workgroup> dst_nested : array<array<array<i32, 2>, 3>, 4>;