Improve help of short-only options (remove dangling comma)

include/cxxopts.hpp

@@ -1468,7 +1468,11 @@ namespace cxxopts
 
       if (!s.empty())
       {
-        result += "-" + toLocalString(s) + ",";
+        result += "-" + toLocalString(s);
+        if (!l.empty())
+        {
+          result += ",";
+        }
       }
       else
       {

src/example.cpp

@@ -49,6 +49,7 @@ parse(int argc, char* argv[])
       ("i,input", "Input", cxxopts::value<std::string>())
       ("o,output", "Output file", cxxopts::value<std::string>()
           ->default_value("a.out")->implicit_value("b.def"), "BIN")
+      ("x", "A short-only option", cxxopts::value<std::string>())
       ("positional",
         "Positional arguments: these are the arguments that are entered "
         "without an option", cxxopts::value<std::vector<std::string>>())