update zh-cn/application-dev/reference/apis/js-apis-eventhub.md.

Signed-off-by: NLiAn <lian15@huawei.com>

zh-cn/application-dev/reference/apis/js-apis-eventhub.md

@@ -133,7 +133,7 @@ emit(event: string, ...args: Object[]): void;
           // func1 is called,1,2
           this.context.eventHub.emit("123", 1, 2);
       }
-      func1(a: string, b: string) {
+      func1(a, b) {
           console.log("func1 is called," + a + "," + b);
       }
   }