Fix typo

Lost my train of thought while typing this.

src/Lexer.c

@@ -124,7 +124,7 @@ static int ReadCharLiteral() {
             case '"': return '"';
             case '\'': return '\'';
             default:
-                DieChar("Unknown Escape: ", c);
+                DieChar("Unknown Escape: ", Char);
         }
     }