Update container-lifecycle-hooks.md

To follow the same logic like the one for describing the **PreStop** hook, I think it's better to write it kike that.

content/en/docs/concepts/containers/container-lifecycle-hooks.md

@@ -30,7 +30,7 @@ There are two hooks that are exposed to Containers:
 
 `PostStart`
 
-This hook executes immediately after a container is created.
+This hook is executed immediately after a container is created.
 However, there is no guarantee that the hook will execute before the container ENTRYPOINT.
 No parameters are passed to the handler.