[Wontdo] Edit shortcuts: add a shortcut to Edit shortcuts

[es]

It's very useful when setting shortcuts initially to be able to invoke the shortcut editor with a shortcut

(sorry if this is a dupe, but forum didn't allow me to search for such common words even after I quoted them as a phrase)

[forum_adm]

This command is not much used. So, a will not assign a standard shortcut.