Override alias template to preserve anchor fragment

[jolheiser]

This PR fixes an annoyance where docs aliases aren't preserving their anchor fragments.

The refactor included aliases to keep old links from dying, but currently they redirect without their anchor, which was used often to jump to sections.

This overrides the alias template with an alternative that preserves the anchor fragment.

To note, this is just a copy of the embedded template, but defaults to a JS redirect that preserves the anchor, and uses the meta tag as a fallback for noscript users.

I've also preserved query params, but I can remove that if we don't think it's necessary.

[delvh]

I think it would be best if this was fixed upstream, but while that's not done I'm fine with that workaround.

[jolheiser]

I think it would be best if this was fixed upstream, but while that's not done I'm fine with that workaround.

I can take a look and propose it upstream as well. 👍
But this is currently happening, so would be good to merge for now either way.