Review wording of SafeMath need in Solidity 0.8 (#2898)

contracts/utils/math/SafeMath.sol

@@ -9,7 +9,7 @@ pragma solidity ^0.8.0;
 /**
  * @dev Wrappers over Solidity's arithmetic operations.
  *
- * NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
+ * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
  * now has built in overflow checking.
  */
 library SafeMath {