Doc: Minor typo fix

Author: frankfarzan

site/book/04-using-functions/02-imperative-function-execution.md

@@ -8,7 +8,7 @@ hierarchy:
 $ kpt fn eval wordpress --image gcr.io/kpt-fn/set-namespace:v0.1 -- namespace=mywordpress
 ```
 
-Alternatively, for convenience, you can use the short-hand form of the above command
+Alternatively, for convenience, you can use the short-hand form of the above command:
 
 ```shell
 $ kpt fn eval wordpress -i set-namespace:v0.1 -- namespace=mywordpress