Fix formatting for make:activity command in docs

Author: rmcdaniel

docs/defining-workflows/activities.md

@@ -6,7 +6,7 @@ sidebar_position: 2
 
 An activity is a unit of work that performs a specific task or operation (e.g. making an API request, processing data, sending an email) and can be executed by a workflow.
 
-You may use the make:activity artisan command to generate a new activity:
+You may use the `make:activity` artisan command to generate a new activity:
 
 ```php
 php artisan make:activity MyActivity