Fix #500

docs/setup.en.md

@@ -14,8 +14,8 @@ If you can use Docker, please see [Setup with Docker](./docker.en.md).
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 Misskey requires two domains called the primary domain and the secondary domain.
 
-* The primary domain is used to provide main service of Misskey.
-* The secondary domain is used to avoid vulnerabilities such as XSS.
+* The primary-domain is used to provide the main service of Misskey.
+* The secondary-domain is used to avoid vulnerabilities such as XSS.
 
 **Ensure that the secondary domain is not a subdomain of the primary domain.**