Geometry Nodes: new Material Assign node

This adds a new Material Assign node. It can be used to change the
material used by an existing mesh or to assign a material to a mesh
that has been generated from scratch.

Differential Revision: https://developer.blender.org/D11155

release/scripts/startup/nodeitems_builtins.py

@@ -525,6 +525,9 @@ geometry_node_categories = [
         NodeItem("FunctionNodeInputVector"),
         NodeItem("GeometryNodeIsViewport"),
     ]),
+    GeometryNodeCategory("GEO_MATERIAL", "Material", items=[
+        NodeItem("GeometryNodeMaterialAssign"),
+    ]),
     GeometryNodeCategory("GEO_MESH", "Mesh", items=[
         NodeItem("GeometryNodeBoolean"),
         NodeItem("GeometryNodeTriangulate"),