Improve naming of internal variables (#2721)

contracts/utils/Strings.sol

@@ -6,7 +6,7 @@ pragma solidity ^0.8.0;
  * @dev String operations.
  */
 library Strings {
-    bytes16 private constant _ALPHABET = "0123456789abcdef";
+    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
 
     /**
      * @dev Converts a `uint256` to its ASCII `string` decimal representation.
@@ -57,7 +57,7 @@ library Strings {
         buffer[0] = "0";
         buffer[1] = "x";
         for (uint256 i = 2 * length + 1; i > 1; --i) {
-            buffer[i] = _ALPHABET[value & 0xf];
+            buffer[i] = _HEX_SYMBOLS[value & 0xf];
             value >>= 4;
         }
         require(value == 0, "Strings: hex length insufficient");

contracts/utils/cryptography/draft-EIP712.sol

@@ -74,10 +74,10 @@ abstract contract EIP712 {
 
     function _buildDomainSeparator(
         bytes32 typeHash,
-        bytes32 name,
+        bytes32 nameHash,
-        bytes32 version
+        bytes32 versionHash
     ) private view returns (bytes32) {
-        return keccak256(abi.encode(typeHash, name, version, block.chainid, address(this)));
+        return keccak256(abi.encode(typeHash, nameHash, versionHash, block.chainid, address(this)));
     }
 
     /**