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/vk-gl-cts/graphicsfuzz/cov-value-tracking-apint-inst-combine-simplify-one-mod-loop-iterator/0-opt.wgsl b/test/vk-gl-cts/graphicsfuzz/cov-value-tracking-apint-inst-combine-simplify-one-mod-loop-iterator/0-opt.wgsl
index 4c3b34b..18e91bc 100644
--- a/test/vk-gl-cts/graphicsfuzz/cov-value-tracking-apint-inst-combine-simplify-one-mod-loop-iterator/0-opt.wgsl
+++ b/test/vk-gl-cts/graphicsfuzz/cov-value-tracking-apint-inst-combine-simplify-one-mod-loop-iterator/0-opt.wgsl
@@ -1,10 +1,10 @@
-type Arr = [[stride(16)]] array<i32, 4>;
+type Arr = @stride(16) array<i32, 4>;
 
 struct buf0 {
   x_GLF_uniform_int_values : Arr;
 };
 
-[[group(0), binding(0)]] var<uniform> x_6 : buf0;
+@group(0) @binding(0) var<uniform> x_6 : buf0;
 
 var<private> x_GLF_color : vec4<f32>;
 
@@ -52,11 +52,11 @@
 }
 
 struct main_out {
-  [[location(0)]]
+  @location(0)
   x_GLF_color_1 : vec4<f32>;
 };
 
-[[stage(fragment)]]
+@stage(fragment)
 fn main() -> main_out {
   main_1();
   return main_out(x_GLF_color);