Remove a useless "public" keyword use in arguments.hpp

src/headers/arguments.hpp

@@ -48,7 +48,7 @@ protected:
     }
 };
 
-struct ArgumentShort: public Argument {
+struct ArgumentShort: Argument {
     const string shortVersion;
     ArgumentShort(string shortName, string name): Argument(move(name)), shortVersion(move(shortName)) {}
     explicit ArgumentShort(string name): ArgumentShort(string(1, name.at(0)), name) {}