Fix typo in email-not-sending.md (#1831)

Author: JLoosman

content/collections/troubleshooting/email-not-sending.md

@@ -27,7 +27,7 @@ Locally, run the queue worker:
 php artisan queue:listen
 ```
 
-Or on production, make sure you a worker configured to run the `queue:work` command.
+Or on production, make sure you have a worker configured to run the `queue:work` command.
 
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