Update gettingstarted.rst

Author: i0bs

docs/gettingstarted.rst

@@ -64,6 +64,8 @@ the *logical* part of our code, the command function:
 - ``ctx.respond()``: This is a way for us to handle responses. In short, the API
 requires some way to "acknowledge" an interaction response that we want to send off.
 
+(An alias of this would be ``ctx.ack()``)
+
 Giving some options for variety.
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