add missing ":" to onion location header
I think the web-server is down because the config for the new Onion-Location
header is broken.
(or actually the syntax in tor docs isn't working: https://community.torproject.org/onion-services/advanced/onion-location/)
This change makes the config line look exactly the same way all other header lines look. So let's hope this fixes it.
Edited by Michael Pöhn