fix: missing "

Author: Lulalaby

docs/extensions/commands/prefixed-commands.mdx

@@ -299,7 +299,7 @@ import random
 async def gtn(ctx, guess:int):
     number = random.randint(1, 10)
     if guess == number:
-        await ctx.send("You guessed it!)
+        await ctx.send("You guessed it!")
     else:
         await ctx.send("Nope! Better luck next time :)")
 ```