HLSL: Additional attribute support: [[]], namespace, parameters:

- support C++11 style brackets [[...]]
- support namespaces [[vk::...]]
- support these on parameter declarations in functions
- support location, binding/set, input attachments

Test/hlsl.attributeC11.frag

@@ -0,0 +1,18 @@
+struct S {
+    float2 f;
+};
+
+[[vk::binding(1)]]
+StructuredBuffer<S> buffer1;
+
+[[vk::binding(3, 2)]]
+StructuredBuffer<S> buffer3;
+
+[[vk::input_attachment_index(4)]]
+Texture2D<float4> attach;
+
+[[vk::location(7)]] float4
+main([[vk::location(8)]] float4 input: A) : B
+{
+    return input + attach.Load(float2(0.5));
+}