Update README.md

Author: ThomasTJdev

README.md

@@ -187,7 +187,7 @@ proc mqttSub() {.async.} =
 
   await ctx.subscribe("nmqtt", 2, on_data)
 
-asyncCheck mqttSub
+asyncCheck mqttSub()
 runForever()
 ```
 
@@ -413,4 +413,4 @@ You can use this to ensure, that all your of messages are sent, before
 exiting your program.
 
 
-____
+____