invoke.mdx: states transition synchronously

Author: audionerd

docs/invoke.mdx

@@ -121,7 +121,7 @@ For further examples, see:
 
 ## How are Actors Different From Actions?
 
-Actions are “fire-and-forget”; as soon as their execution starts, the state machine running the actions forgets about them. If you specify an action as `async`, **the action won’t be awaited before moving to the next state**. Remember: transitions are always _zero-time_.
+Actions are “fire-and-forget”; as soon as their execution starts, the state machine running the actions forgets about them. If you specify an action as `async`, **the action won’t be awaited before moving to the next state**. Remember: transitions are always _zero-time_ (states transition synchronously).
 
 Invoked actors can do asynchronous work _and_ communicate with their parent machine actor. They they can send and receive events. Invoked machine actors can even invoke or spawn their own child actors.