Merge pull request #530 from SparkPost/fix/broken-unsubscribe-link

Fix broken link to guide on unsubscribe links

Author: rdawemsys

content/api/template-language.apib

@@ -579,7 +579,7 @@ You can configure a link in your content to generate a `link_unsubscribe` event
 <a href="http://www.example.com/unsub_handler?id=1234" data-msys-unsubscribe="1">Unsubscribe</a>
 ```
 
-More information can be found [here](https://support.sparkpost.com/customer/portal/articles/1929894-setting-up-unsubscribe-links).
+More information can be found [here](https://support.sparkpost.com/docs/user-guide/setting-up-unsubscribe-links/).
 
 #### Per-link Disabling of Click Tracking