move fork constant and tag fork branch with comment

build/forks.go

@@ -1,3 +1,3 @@
 package build
 
-// No forks yet \o/
+const ForkBlizzardHeight = 6000

build/params_shared.go

@@ -105,9 +105,3 @@ const BlsSignatureCacheSize = 40000
 // Limits
 
 const BlockMessageLimit = 512
-
-/////////////
-// Fork Heights
-//
-
-const ForkBlizzardHeight = 6000

chain/actors/actor_storagepower.go

@@ -138,6 +138,7 @@ func (spa StoragePowerActor) ArbitrateConsensusFault(act *types.Actor, vmctx typ
 		return nil, aerrors.New(2, "blocks must be from the same miner")
 	}
 
+	// FORK
 	if vmctx.BlockHeight() > build.ForkBlizzardHeight {
 		if params.Block1.Cid() == params.Block2.Cid() {
 			return nil, aerrors.New(3, "blocks must be different")