Add fmapCoerce to Functor class.
Add fmapCoerce to Functor class.

This allows coercions to work under functors that are not locally known.

Authored-by: Edward Kmett <6ed452734e05f476dcb27611d798f6c1f2e74de0@gmail.com>
Signed-off-by: Austin Seipp <7ea35d812706d9213868749011af1ed4fa2f6aa0@well-typed.com>

TomMD/ghc,forked-upstream-packages-for-ghcjs/ghc,jstolarek/ghc,tibbe/ghc,olsner/ghc,nathyong/microghc-ghc,nathyong/microghc-ghc,vikraman/ghc,sdiehl/ghc,anton-dessiatov/ghc,oldmanmike/ghc,mfine/ghc,wxwxwwxxx/ghc,gcampax/ghc,da-x/ghc,nkaretnikov/ghc,mettekou/ghc,shlevy/ghc,christiaanb/ghc,acowley/ghc,bitemyapp/ghc,snoyberg/ghc,vikraman/ghc,vikraman/ghc,oldmanmike/ghc,ml9951/ghc,mfine/ghc,olsner/ghc,mfine/ghc,forked-upstream-packages-for-ghcjs/ghc,elieux/ghc,sgillespie/ghc,anton-dessiatov/ghc,ghc-android/ghc,nkaretnikov/ghc,fmthoma/ghc,anton-dessiatov/ghc,snoyberg/ghc,bitemyapp/ghc,anton-dessiatov/ghc,forked-upstream-packages-for-ghcjs/ghc,nathyong/microghc-ghc,gridaphobe/ghc,oldmanmike/ghc,ghc-android/ghc,gridaphobe/ghc,urbanslug/ghc,forked-upstream-packages-for-ghcjs/ghc,ryantm/ghc,nathyong/microghc-ghc,snoyberg/ghc,mettekou/ghc,GaloisInc/halvm-ghc,sdiehl/ghc,bitemyapp/ghc,nushio3/ghc,gridaphobe/ghc,sdiehl/ghc,ezyang/ghc,AlexanderPankiv/ghc,christiaanb/ghc,nushio3/ghc,mfine/ghc,oldmanmike/ghc,siddhanathan/ghc,ml9951/ghc,sdiehl/ghc,siddhanathan/ghc,TomMD/ghc,GaloisInc/halvm-ghc,nkaretnikov/ghc,anton-dessiatov/ghc,siddhanathan/ghc,lukexi/ghc,GaloisInc/halvm-ghc,vTurbine/ghc,fmthoma/ghc,christiaanb/ghc,mettekou/ghc,tibbe/ghc,frantisekfarka/ghc-dsi,oldmanmike/ghc,ryantm/ghc,mcschroeder/ghc,sgillespie/ghc,forked-upstream-packages-for-ghcjs/ghc,gridaphobe/ghc,christiaanb/ghc,nushio3/ghc,mcschroeder/ghc,sgillespie/ghc,tjakway/ghcjvm,olsner/ghc,siddhanathan/ghc,GaloisInc/halvm-ghc,gridaphobe/ghc,olsner/ghc,AlexanderPankiv/ghc,elieux/ghc,nkaretnikov/ghc,shlevy/ghc,anton-dessiatov/ghc,ryantm/ghc,jstolarek/ghc,gridaphobe/ghc,tjakway/ghcjvm,gcampax/ghc,frantisekfarka/ghc-dsi,gridaphobe/ghc,ghc-android/ghc,vTurbine/ghc,mcschroeder/ghc,GaloisInc/halvm-ghc,ghc-android/ghc,green-haskell/ghc,ml9951/ghc,acowley/ghc,shlevy/ghc,sgillespie/ghc,ml9951/ghc,ryantm/ghc,jstolarek/ghc,da-x/ghc,lukexi/ghc,elieux/ghc,mettekou/ghc,mettekou/ghc,spacekitteh/smcghc,mcschroeder/ghc,nkaretnikov/ghc,ezyang/ghc,jstolarek/ghc,shlevy/ghc,tjakway/ghcjvm,sgillespie/ghc,holzensp/ghc,tibbe/ghc,shlevy/ghc,da-x/ghc,elieux/ghc,spacekitteh/smcghc,snoyberg/ghc,sgillespie/ghc,da-x/ghc,forked-upstream-packages-for-ghcjs/ghc,urbanslug/ghc,tibbe/ghc,frantisekfarka/ghc-dsi,christiaanb/ghc,AlexanderPankiv/ghc,nushio3/ghc,vikraman/ghc,green-haskell/ghc,urbanslug/ghc,elieux/ghc,wxwxwwxxx/ghc,da-x/ghc,mettekou/ghc,acowley/ghc,wxwxwwxxx/ghc,nathyong/microghc-ghc,ml9951/ghc,GaloisInc/halvm-ghc,wxwxwwxxx/ghc,gcampax/ghc,nushio3/ghc,jstolarek/ghc,tjakway/ghcjvm,wxwxwwxxx/ghc,mettekou/ghc,frantisekfarka/ghc-dsi,vTurbine/ghc,AlexanderPankiv/ghc,olsner/ghc,siddhanathan/ghc,fmthoma/ghc,vTurbine/ghc,nushio3/ghc,olsner/ghc,tjakway/ghcjvm,wxwxwwxxx/ghc,tjakway/ghcjvm,acowley/ghc,fmthoma/ghc,ezyang/ghc,sdiehl/ghc,fmthoma/ghc,vikraman/ghc,siddhanathan/ghc,acowley/ghc,snoyberg/ghc,green-haskell/ghc,ghc-android/ghc,TomMD/ghc,wxwxwwxxx/ghc,frantisekfarka/ghc-dsi,ml9951/ghc,fmthoma/ghc,TomMD/ghc,tjakway/ghcjvm,da-x/ghc,ezyang/ghc,lukexi/ghc,sdiehl/ghc,green-haskell/ghc,shlevy/ghc,nkaretnikov/ghc,sgillespie/ghc,TomMD/ghc,vikraman/ghc,AlexanderPankiv/ghc,forked-upstream-packages-for-ghcjs/ghc,vTurbine/ghc,gcampax/ghc,AlexanderPankiv/ghc,holzensp/ghc,ryantm/ghc,TomMD/ghc,oldmanmike/ghc,oldmanmike/ghc,ml9951/ghc,ml9951/ghc,nushio3/ghc,acowley/ghc,nathyong/microghc-ghc,sdiehl/ghc,mcschroeder/ghc,elieux/ghc,christiaanb/ghc,bitemyapp/ghc,bitemyapp/ghc,nkaretnikov/ghc,mfine/ghc,mfine/ghc,ezyang/ghc,anton-dessiatov/ghc,siddhanathan/ghc,ghc-android/ghc,gcampax/ghc,snoyberg/ghc,lukexi/ghc,acowley/ghc,AlexanderPankiv/ghc,urbanslug/ghc,ezyang/ghc,snoyberg/ghc,nathyong/microghc-ghc,mcschroeder/ghc,vikraman/ghc,da-x/ghc,spacekitteh/smcghc,urbanslug/ghc,spacekitteh/smcghc,christiaanb/ghc,olsner/ghc,mfine/ghc,ezyang/ghc,gcampax/ghc,holzensp/ghc,elieux/ghc,gcampax/ghc,urbanslug/ghc,tibbe/ghc,mcschroeder/ghc,vTurbine/ghc,GaloisInc/halvm-ghc,holzensp/ghc,fmthoma/ghc,urbanslug/ghc,spacekitteh/smcghc,green-haskell/ghc,TomMD/ghc,vTurbine/ghc,shlevy/ghc,lukexi/ghc,holzensp/ghc,ghc-android/ghc