Fix mkdocs site_url to path-based docs URL

Docs are served at docs.cryptuon.com/<project>/, not at the
<project>.docs subdomain. Sitemap and canonical tags now match.

Author: dnscap-bot

documentation/mkdocs.yml

@@ -1,7 +1,7 @@
 site_name: ChainSync Documentation
 site_description: Unified Cross-Chain State Synchronization Platform - Deploy once, sync everywhere
 site_author: ChainSync Team
-site_url: https://switchboard.docs.cryptuon.com/
+site_url: https://docs.cryptuon.com/switchboard/
 
 repo_name: cryptuon/switchboard
 repo_url: https://github.com/cryptuon/switchboard