Syntax checker does not support HLSL Dynamic Resources

[dreamer1995]

There is something new in shader model 6.6, dynamic resources. https://microsoft.github.io/DirectX-Specs/d3d/HLSL_SM_6_6_DynamicResources.html
However, the syntax checker will report "HLSL0033 Variable 'ResourceDescriptorHeap' is not declared.".
ResourceDescriptorHeap is a built-in variable in shader model 6.6.