add isShadow flag if a node is under shadow root

typings/index.d.ts

@@ -1,4 +1,5 @@
 import snapshot, { serializeNodeWithId, transformAttribute, visitSnapshot, cleanupSnapshot, IGNORED_NODE } from './snapshot';
 import rebuild, { buildNodeWithSN, addHoverClass } from './rebuild';
 export * from './types';
+export * from './utils';
 export { snapshot, serializeNodeWithId, rebuild, buildNodeWithSN, addHoverClass, transformAttribute, visitSnapshot, cleanupSnapshot, IGNORED_NODE, };