no longer need to pass --allow-missing-html to haddock
no longer need to pass --allow-missing-html to haddock

This option only affects Haddock if it is invoked with --use-package,
and Cabal no longer uses that option, as it now gets the arguments for
--read-interface from ghc-pkg directly (cf patch "rejig location of
package interfaces for haddock").


IreneKnapp/Faction,IreneKnapp/Faction