Merge pull request #1299 from Unity-Technologies/stacklit

Enable coat effect on diffuse lighting.

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/StackLit/StackLit.hlsl

 //#define VLAYERED_RECOMPUTE_PERLIGHT // TODO test more, make it a shader_features
 // probably too slow but just to check the difference it makes
 //#define VLAYERED_USE_REFRACTED_ANGLES_FOR_BASE
-//#define VLAYERED_DIFFUSE_ENERGY_HACKED_TERM
+#define VLAYERED_DIFFUSE_ENERGY_HACKED_TERM
 //#define VLAYERED_ANISOTROPY_IBL_DESTRETCH
 
 #define VLAYERED_ANISOTROPY_SCALAR_ROUGHNESS