Minor : add details to PreIntegratedGFGD comment

Assets/ScriptableRenderLoop/HDRenderLoop/HDRenderLoop.cs

     clip(builtinData.opacity - _AlphaCutoff);
 #endif
 
-    /* HotFix to keep the PreIntegratedFGD shared texture sampler */
+    /* HotFix to keep the PreIntegratedFGD shared texture sampler (TODO : workaround until we support independant sampler declaration)*/
     surfaceData.specularOcclusion = max(surfaceData.specularOcclusion, 10e-5f);
 }