Clarify trial extensions (#391)

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Documentation**
* Clarified behavior when trial licenses expire, including purchase and
extension options.
* Updated trial extension policy: each extension now provides 15 days
(previously 14 days).
  * Updated support resources for trial extension requests.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: ljm42

docs/unraid-os/troubleshooting/licensing-faq.mdx

@@ -180,11 +180,12 @@ This error indicates that your USB flash device does not have a unique hardware
 - You'll need a quality USB flash drive and the Unraid USB Creator tool.
 - Consult the [Getting Started guide](../getting-started/set-up-unraid/create-your-bootable-media.mdx) for server setup instructions.
 - Trial licenses require an internet connection at boot for initial validation.
+- When your trial expires, the array will stop. You may then purchase a license key or request a trial extension.
 - You can extend your trial for 15 more days if you need more time to evaluate Unraid. You can do this twice for a total of 60 days (details below).
 
 ### How do I extend my trial? {#extend-trial}
 
-Unraid trial registration keys last for 30 days and can be extended twice for 14 additional days each time. After two trial extensions, no additional extensions can be granted. To request an extension, you must stop the array, navigate to the **Tools > Registration** page, and click "Request Extension."
+Unraid trial registration keys last for 30 days and can be extended twice for 15 additional days each time. After two trial extensions, no additional extensions can be granted. To request an extension, you must stop the array, navigate to the **Tools > Registration** page, and click "Request Extension."
 
 If the two additional extensions were not used and this option does not appear for you, or if it's not working for any reason, please send us the flash drive GUID from **Tools > Registration** to [[email protected]](mailto:[email protected]) or via our support portal at [support.unraid.net](https://support.unraid.net/support/home) and we will be happy to assist.