In #5493 jekyll-redirect-from was added for redirects, and it works.

But there are links to docs with hash params in examples, which are all redirected to http://leafletjs.com/reference-1.2.0.html instead of http://leafletjs.com/reference-1.2.0.html#hash.
See L.Icon link in Custom Icons example.

Since jekyll-redirect-from does not preserve hash params, I removed it and used redirected.html layout, which I modified to preserve hash params.

I also fixed some absolute links, and changed some links from specific docs version to latest.

So now it is possible to refer latest docs with hash like that:

[LatLng](/reference.html#latlng)

and it will redirect to docs version defined in main reference.html file.

Tested locally, it should work.