Add access for changing the 3D preview stage in mesh viewer

qrenderdoc/Code/Interface/QRDInterface.h

@@ -572,6 +572,13 @@ buffer view.
 )");
   virtual void SetCurrentView(int32_t view) = 0;
 
+  DOCUMENT(R"(For a mesh view, set the current preview stage. This is ignored when called on a raw
+buffer view.
+
+:param MeshDataStage stage: The stage to show
+)");
+  virtual void SetPreviewStage(MeshDataStage stage) = 0;
+
 protected:
   IBufferViewer() = default;
   ~IBufferViewer() = default;