Function Nodes: Input Vector

Ref: T82651

Normally people use "Combine XYZ" to input a vector, but it is more
interesting to have an explicit vector input.

So this is basically "Combine XYZ" without any input sockets, the values
are stored in the node itself.

Differential Revision: https://developer.blender.org/D9885

release/scripts/startup/nodeitems_builtins.py

@@ -502,6 +502,7 @@ geometry_node_categories = [
         NodeItem("GeometryNodeObjectInfo"),
         NodeItem("FunctionNodeRandomFloat"),
         NodeItem("ShaderNodeValue"),
+        NodeItem("FunctionNodeInputVector"),
     ]),
     GeometryNodeCategory("GEO_MESH", "Mesh", items=[
         NodeItem("GeometryNodeTriangulate"),