Geometry Nodes: new Material input node

This node is similar to the Value and Vector node.
It just provides a way to use the same material in multiple nodes
without exposing it outside of a node group.

Differential Revision: https://developer.blender.org/D11305

release/scripts/startup/nodeitems_builtins.py

@@ -523,6 +523,7 @@ geometry_node_categories = [
         NodeItem("ShaderNodeValue"),
         NodeItem("FunctionNodeInputString"),
         NodeItem("FunctionNodeInputVector"),
+        NodeItem("GeometryNodeInputMaterial"),
         NodeItem("GeometryNodeIsViewport"),
     ]),
     GeometryNodeCategory("GEO_MATERIAL", "Material", items=[