Thank you for contacting us!
What seems to be a workaround for your question for the time being is the following:
In the HTML included in the <head> tag (except title, keywords, description)
section of the Page properties you can manually add the link tag with all attributes you want. Also, make sure to disable the Canonical URL
option from the drop-down above.
As far as auto-generation of these is concerned, this might become part of future product roadmaps.
I hope this information helps.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items