Blender Git Loki

Fix #31908, better drawing for node group interface links. Links from/to node group internal sockets (input/output columns on the side) were drawn in a kind of subtle "background" mode, making them hard to see behind nodes. This was still from pre-2.56.2 versions, where group interfaces were created automatically and these links were just indicators of which external socket a node refers to.

Now these links are drawn in the same way as all others. Also they now display highlighting correctly when inserting a node into a link, making it easier to avoid unwanted insertions.