Add details box to BatchCommandDialog

It is now populated with the CommandID and the command type.
Later we can add the command help string.

Std::pair changed to std::tuple to accommodate the extra information.

src/BatchCommands.h

@@ -12,6 +12,7 @@
 #ifndef __AUDACITY_BATCH_COMMANDS_DIALOG__
 #define __AUDACITY_BATCH_COMMANDS_DIALOG__
 
+#include <tuple>
 #include <wx/defs.h>
 #include <wx/string.h>
 
@@ -43,7 +44,7 @@ class BatchCommands final {
    static wxArrayString GetNames();
 
    // A pair of user-visible name, and internal string identifier
-   using CommandName = std::pair<wxString, wxString>;
+   using CommandName = std::tuple<wxString, wxString, wxString>;
    using CommandNameVector = std::vector<CommandName>;
    // Result is sorted by user-visible name
    static CommandNameVector GetAllCommands();