Don't warn about missing '~' (#746)
Don't warn about missing '~' (#746)

This manually filters out '~' from the list of things to warn about. It truly
makes no sense to warn on this since '~' has nothing it could link to - it is
magical.

This fixes #532.
haskell/haddock,haskell/haddock,haskell/haddock,haskell/haddock,haskell/haddock