adding further documentation and explanation to the prefetch primops
adding further documentation and explanation to the prefetch primops

Signed-off-by: Carter Tazio Schonwald <ee0eec66ed2194a53075ca582f8de9abd084a40f@gmail.com>
Signed-off-by: Austin Seipp <7ea35d812706d9213868749011af1ed4fa2f6aa0@well-typed.com>

mettekou/ghc,sdiehl/ghc,sdiehl/ghc,mfine/ghc,sdiehl/ghc,vTurbine/ghc,anton-dessiatov/ghc,da-x/ghc,mfine/ghc,christiaanb/ghc,gcampax/ghc,nkaretnikov/ghc,anton-dessiatov/ghc,ghc-android/ghc,wxwxwwxxx/ghc,ml9951/ghc,holzensp/ghc,gcampax/ghc,wxwxwwxxx/ghc,elieux/ghc,spacekitteh/smcghc,fmthoma/ghc,lukexi/ghc,ghc-android/ghc,olsner/ghc,christiaanb/ghc,nushio3/ghc,spacekitteh/smcghc,elieux/ghc,shlevy/ghc,elieux/ghc,GaloisInc/halvm-ghc,holzensp/ghc,gridaphobe/ghc,sgillespie/ghc,mcschroeder/ghc,TomMD/ghc,urbanslug/ghc,oldmanmike/ghc,lukexi/ghc,siddhanathan/ghc,sgillespie/ghc,hferreiro/replay,AlexanderPankiv/ghc,wxwxwwxxx/ghc,AlexanderPankiv/ghc,anton-dessiatov/ghc,siddhanathan/ghc,forked-upstream-packages-for-ghcjs/ghc,shlevy/ghc,frantisekfarka/ghc-dsi,TomMD/ghc,vikraman/ghc,hferreiro/replay,ghc-android/ghc,forked-upstream-packages-for-ghcjs/ghc,hferreiro/replay,fmthoma/ghc,vTurbine/ghc,snoyberg/ghc,wxwxwwxxx/ghc,lukexi/ghc-7.8-arm64,urbanslug/ghc,da-x/ghc,mcschroeder/ghc,ml9951/ghc,christiaanb/ghc,nathyong/microghc-ghc,mfine/ghc,christiaanb/ghc,ryantm/ghc,ryantm/ghc,vikraman/ghc,wxwxwwxxx/ghc,nathyong/microghc-ghc,mettekou/ghc,lukexi/ghc,GaloisInc/halvm-ghc,lukexi/ghc,sgillespie/ghc,oldmanmike/ghc,ryantm/ghc,tjakway/ghcjvm,hferreiro/replay,gcampax/ghc,forked-upstream-packages-for-ghcjs/ghc,vikraman/ghc,acowley/ghc,siddhanathan/ghc,christiaanb/ghc,tjakway/ghcjvm,sgillespie/ghc,anton-dessiatov/ghc,vTurbine/ghc,oldmanmike/ghc,nushio3/ghc,gcampax/ghc,urbanslug/ghc,GaloisInc/halvm-ghc,nushio3/ghc,spacekitteh/smcghc,mcschroeder/ghc,nkaretnikov/ghc,olsner/ghc,mfine/ghc,mettekou/ghc,anton-dessiatov/ghc,siddhanathan/ghc,tjakway/ghcjvm,holzensp/ghc,jstolarek/ghc,tibbe/ghc,oldmanmike/ghc,tibbe/ghc,ezyang/ghc,olsner/ghc,gridaphobe/ghc,TomMD/ghc,acowley/ghc,nushio3/ghc,nathyong/microghc-ghc,oldmanmike/ghc,mcschroeder/ghc,mcschroeder/ghc,olsner/ghc,nathyong/microghc-ghc,GaloisInc/halvm-ghc,ezyang/ghc,ezyang/ghc,lukexi/ghc-7.8-arm64,sdiehl/ghc,ghc-android/ghc,tjakway/ghcjvm,da-x/ghc,tjakway/ghcjvm,AlexanderPankiv/ghc,AlexanderPankiv/ghc,bitemyapp/ghc,vikraman/ghc,GaloisInc/halvm-ghc,snoyberg/ghc,da-x/ghc,ghc-android/ghc,christiaanb/ghc,shlevy/ghc,snoyberg/ghc,fmthoma/ghc,mfine/ghc,urbanslug/ghc,mfine/ghc,siddhanathan/ghc,christiaanb/ghc,AlexanderPankiv/ghc,forked-upstream-packages-for-ghcjs/ghc,gcampax/ghc,da-x/ghc,mettekou/ghc,anton-dessiatov/ghc,lukexi/ghc-7.8-arm64,mfine/ghc,elieux/ghc,siddhanathan/ghc,vikraman/ghc,sgillespie/ghc,elieux/ghc,nkaretnikov/ghc,frantisekfarka/ghc-dsi,holzensp/ghc,ezyang/ghc,hferreiro/replay,sgillespie/ghc,AlexanderPankiv/ghc,mettekou/ghc,elieux/ghc,GaloisInc/halvm-ghc,gridaphobe/ghc,TomMD/ghc,urbanslug/ghc,fmthoma/ghc,mcschroeder/ghc,ml9951/ghc,siddhanathan/ghc,ml9951/ghc,oldmanmike/ghc,olsner/ghc,vTurbine/ghc,GaloisInc/halvm-ghc,wxwxwwxxx/ghc,snoyberg/ghc,fmthoma/ghc,ml9951/ghc,sdiehl/ghc,acowley/ghc,spacekitteh/smcghc,ghc-android/ghc,sdiehl/ghc,AlexanderPankiv/ghc,nkaretnikov/ghc,vikraman/ghc,green-haskell/ghc,nathyong/microghc-ghc,green-haskell/ghc,sgillespie/ghc,ml9951/ghc,acowley/ghc,ezyang/ghc,tjakway/ghcjvm,green-haskell/ghc,tibbe/ghc,anton-dessiatov/ghc,frantisekfarka/ghc-dsi,jstolarek/ghc,jstolarek/ghc,gridaphobe/ghc,gridaphobe/ghc,nushio3/ghc,nkaretnikov/ghc,acowley/ghc,forked-upstream-packages-for-ghcjs/ghc,vTurbine/ghc,vikraman/ghc,lukexi/ghc,elieux/ghc,wxwxwwxxx/ghc,urbanslug/ghc,oldmanmike/ghc,green-haskell/ghc,nkaretnikov/ghc,da-x/ghc,tibbe/ghc,ezyang/ghc,spacekitteh/smcghc,da-x/ghc,green-haskell/ghc,ezyang/ghc,nathyong/microghc-ghc,bitemyapp/ghc,nkaretnikov/ghc,shlevy/ghc,gcampax/ghc,TomMD/ghc,jstolarek/ghc,hferreiro/replay,ryantm/ghc,nushio3/ghc,lukexi/ghc-7.8-arm64,hferreiro/replay,vTurbine/ghc,olsner/ghc,frantisekfarka/ghc-dsi,bitemyapp/ghc,shlevy/ghc,fmthoma/ghc,holzensp/ghc,frantisekfarka/ghc-dsi,ghc-android/ghc,ryantm/ghc,tibbe/ghc,bitemyapp/ghc,nushio3/ghc,ml9951/ghc,mettekou/ghc,sdiehl/ghc,shlevy/ghc,urbanslug/ghc,acowley/ghc,acowley/ghc,bitemyapp/ghc,ml9951/ghc,vTurbine/ghc,jstolarek/ghc,gridaphobe/ghc,forked-upstream-packages-for-ghcjs/ghc,fmthoma/ghc,gridaphobe/ghc,gcampax/ghc,mettekou/ghc,shlevy/ghc,snoyberg/ghc,lukexi/ghc-7.8-arm64,TomMD/ghc,snoyberg/ghc,TomMD/ghc,forked-upstream-packages-for-ghcjs/ghc,nathyong/microghc-ghc,snoyberg/ghc,olsner/ghc,tjakway/ghcjvm,mcschroeder/ghc