Offer an option to automatically chop the .html off of canonical URLs

[hakanai]

Leaf pages on my site come out in the metadata as follows:

<link rel="canonical" href="https://mysite.name//external-resources.html" />

I'd prefer to omit the .html from all these. I know I can manually set canonical_url for all my pages, but that would introduce a new problem where if I ever rename a page, I have to manually edit canonical_url to keep it in sync.

I'm not sure that everyone would prefer to remove the .html, though, so I guess it should be a site option.