Fix typo in doc of SignatureChecker (#2881)

contracts/utils/cryptography/SignatureChecker.sol

@@ -8,7 +8,7 @@ import "../../interfaces/IERC1271.sol";
 
 /**
  * @dev Signature verification helper: Provide a single mechanism to verify both private-key (EOA) ECDSA signature and
- * ERC1271 contract sigantures. Using this instead of ECDSA.recover in your contract will make them compatible with
+ * ERC1271 contract signatures. Using this instead of ECDSA.recover in your contract will make them compatible with
  * smart contract wallets such as Argent and Gnosis.
  *
  * Note: unlike ECDSA signatures, contract signature's are revocable, and the outcome of this function can thus change