This patch adds support for the experimental structure types currently
used bu Geometry Nodes. Pixel nodes were declared as function nodes,
which gives dynamic structures for all their sockets. Other nodes now
explicitly declared their inputs as dynamic if not single value, while
the compositor_expects_single_value marker was removed in favor of the
StructureType::Single type.
Pull Request: https://projects.blender.org/blender/blender/pulls/140910
3b1d252431