minor #3725 Minor tweaks related to #3368 (weaverryan)

This PR was merged into the 2.3 branch.

Discussion
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Minor tweaks related to #3368

Hi guys!

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3

Commits
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544a0f5 Minor tweaks related to #3368

components/routing/hostname_pattern.rst

@@ -183,9 +183,9 @@ instance, if you want to match both ``m.example.com`` and
 
     .. tip::
 
-       Make sure you also include a default option for the ``subdomain``
-       placeholder, otherwise you need to include the subdomains value each time
-       you generate the route.
+       Make sure you also include a default option for the ``domain`` placeholder,
+       otherwise you need to include a domain value each time you generate
+       a URL using the route.
 
     .. configuration-block::