Fixed a compiler warning

include/token/TokenType.h

@@ -61,7 +61,7 @@ enum class TokenType
     MINUS_ASSIGN,    ///< Subtract and assign operator (-=)
     MULTIPLY_ASSIGN, ///< Multiply and assign operator (*=)
     DIVIDE_ASSIGN,   ///< Divide and assign operator (/=)
-    PERCENT_ASSIGN,  ///< Modulo and assign operator (%=)
+    MODULO_ASSIGN,   ///< Modulo and assign operator (%=)
 
     // Comparison operators
     EQUAL,         ///< Equality operator (==)

source/token/TokenType.cc

@@ -43,6 +43,7 @@ String token_type_to_string(TokenType token)
     case TokenType::MINUS_ASSIGN: return "-=";
     case TokenType::MULTIPLY_ASSIGN: return "*=";
     case TokenType::DIVIDE_ASSIGN: return "/=";
+    case TokenType::MODULO_ASSIGN: return "%=";
 
     case TokenType::EQUAL: return "==";
     case TokenType::NOT_EQUAL: return "!=";