refactor(util-functions): cleanup types so that node/edge types get infered

packages/svelte/src/lib/index.ts

@@ -112,5 +112,9 @@ export {
   getStraightPath,
   getViewportForBounds,
   getNodesBounds,
+  getIncomers,
+  getOutgoers,
+  getConnectedEdges,
+  addEdge,
   internalsSymbol
 } from '@xyflow/system';