Add link to support page for commercial support (go-gitea#25293) (go-gitea#25299)

Backport go-gitea#25293 by @techknowlogick

Co-authored-by: techknowlogick <[email protected]>

Author: GiteaBot

docs/content/doc/help/seek-help.en-us.md

@@ -15,6 +15,7 @@ menu:
 
 # Support Options
 
+- [Paid Commercial Support](https://about.gitea.com/)
 - [Discord](https://discord.gg/Gitea)
 - [Discourse Forum](https://discourse.gitea.io/)