Added comma

site/content/tutorial/18-debugging/01-debug/text.md

@@ -2,7 +2,7 @@
 title: The @debug tag
 ---
 
-Occasionally it's useful to inspect a piece of data as it flows through your app.
+Occasionally, it's useful to inspect a piece of data as it flows through your app.
 
 One approach is to use `console.log(...)` inside your markup. If you want to pause execution, though, you can use the `{@debug ...}` tag with a comma-separated list of values you want to inspect: