documentation links broken in 7.10.1

[Evan Laforge]

It seems like haddock's index.html generation is broken in 7.10.1.
Namely, it creates links to e.g. Codec-Binary-UTF8-Generic.html when
it should be to utf8-string-1/html/Codec-Binary-UTF8-Generic.html

This is haddock 2.16.0, which comes with the binary distribution for 7.10.1.

I looked at https://github.com/haskell/haddock/issues but didn't see
anything related to this, which makes me think it's just me.  You'd
think someone would notice if all documentation links were broken.

Does anyone else see this?