edit-menu:between-find-and-preferences in drscheme:frame:basics-mixin

This method is called between the addition of the find menu-item and before the addition of the preferences menu-item to the edit-menu menu. Override it to add additional menus at that point.

• (send a-drscheme:frame:basics-mixin edit-menu:between-find-and-preferences) -> void

  Adds the "Keybindings" menu item to the edit menu.