Fix BlockContext comment (#731)

Author: martineckardt

precompile/contract/interfaces.go

@@ -63,9 +63,8 @@ type AccessibleState interface {
 	CallFromPrecompile(caller common.Address, addr common.Address, input []byte, gas uint64, value *big.Int) (ret []byte, leftOverGas uint64, err error)
 }
 
-// BlockContext defines an interface that provides information to a stateful precompile
-// about the block that activates the upgrade. The precompile can access this information
-// to initialize its state.
+// BlockContext defines an interface that provides information to a stateful precompile about the
+// current block. The BlockContext may be provided during both precompile activation and execution.
 type BlockContext interface {
 	Number() *big.Int
 	Timestamp() *big.Int