fix(slots): make compiled slot marker non-enumerable

fix #1470

packages/shared/src/index.ts

@@ -114,6 +114,7 @@ export const invokeArrayFns = (fns: Function[], arg?: any) => {
 export const def = (obj: object, key: string | symbol, value: any) => {
   Object.defineProperty(obj, key, {
     configurable: true,
+    enumerable: false,
     value
   })
 }