+ * @i: the action index corresponding to the action to be performed
+ *
+ * Gets the keybinding which can be used to activate this action, if one
+ * exists. The string returned should contain localized, human-readable,
+ * key sequences as they would appear when displayed on screen. It must
+ * be in the format "mnemonic;sequence;shortcut".
+ *
+ * - The mnemonic key activates the object if it is presently enabled onscreen.
+ * This typically corresponds to the underlined letter within the widget.
+ * Example: "n" in a traditional "New..." menu item or the "a" in "Apply" for
+ * a button.
+ * - The sequence is the full list of keys which invoke the action even if the
+ * relevant element is not currently shown on screen. For instance, for a menu
+ * item the sequence is the keybindings used to open the parent menus before
+ * invoking. The sequence string is colon-delimited. Example: "Alt+F:N" in a
+ * traditional "New..." menu item.
+ * - The shortcut, if it exists, will invoke the same action without showing
+ * the component or its enclosing menus or dialogs. Example: "Ctrl+N" in a
+ * traditional "New..." menu item.
+ *
+ * Example: For a traditional "New..." menu item, the expected return value
+ * would be: "N;Alt+F:N;Ctrl+N" for the English locale and "N;Alt+D:N;Strg+N"
+ * for the German locale. If, hypothetically, this menu item lacked a mnemonic,
+ * it would be represented by ";;Ctrl+N" and ";;Strg+N" respectively.