Rename subgraph widgets when slot is renamed

When a slot is renamed inside a subgraph, the corresponding slots on a
subgraph Node are also renamed. However, widgets on subgraph nodes were
not updated. Since the slot name is not shown when there is a linked
widget, this would give the impression that the rename was not
functional.

If a widget exists on a subgraph node when a rename event is received,
the label on that widget is also set.

src/lib/litegraph/src/subgraph/SubgraphNode.ts

@@ -125,6 +125,9 @@ export class SubgraphNode extends LGraphNode implements BaseLGraph {
         if (!input) throw new Error('Subgraph input not found')
 
         input.label = newName
+        if (input._widget) {
+          input._widget.label = newName
+        }
       },
       { signal }
     )