Clarify limitations of transparent materials in Spatial shaders

tutorials/3d/3d_rendering_limitations.rst

@@ -112,7 +112,7 @@ this feature. There are still several ways to avoid this problem:
 - If you need to render semi-transparent areas of the texture, alpha scissor
   isn't suitable. Instead, setting the StandardMaterial3D's
   **Transparency > Transparency** property to **Depth Pre-Pass** can sometimes
-  work (at a performance cost).
+  work (at a performance cost). You can also try the **Alpha Hash** mode.
 
 - If you want a material to fade with distance, use the StandardMaterial3D
   distance fade mode **Pixel Dither** or **Object Dither** instead of

tutorials/shaders/shader_reference/spatial_shader.rst

@@ -461,3 +461,7 @@ If you want the lights to add together, add the light contribution to ``DIFFUSE_
     may exhibit transparency sorting issues. Read the
     :ref:`transparency sorting section in the 3D rendering limitations page <doc_3d_rendering_limitations_transparency_sorting>`
     for more information and ways to avoid issues.
+
+    Transparent materials also cannot cast shadows or appear in
+    ``SCREEN_TEXTURE`` and ``DEPTH_TEXTURE``. This in turn prevents those
+    materials from appearing in screen-space reflections or refraction.