Feature request: line anchor

[cxplay]

Well, that's one of the things that GitHub and the like have, the ability to use HTML anchors to locate specific lines. But if you're just displaying a diff, maybe it's enough to provide anchors for the diff locations.
example: https://github.com/rtfpessoa/diff2html-cli/blob/18add5d220d624022dd24a303c55f4a63547b65b/template.html#L18