(core) Changing shortcut for Duplicate row command

Summary:
Changing keyboard shortcut for Duplicate row from
Ctrl+Shift+D to Mod+Shift+D

Test Plan: existing test

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3401

app/client/components/commandList.js

@@ -362,7 +362,7 @@ exports.groups = [{
       desc: 'Delete the currently active viewsection'
     }, {
       name: 'duplicateRows',
-      keys: ['Ctrl+Shift+d'],
+      keys: ['Mod+Shift+d'],
       desc: 'Duplicate selected rows'
     }
   ],