Fix Doxygen warning on nestegg_save_state.
Fix Doxygen warning on nestegg_save_state.

fallaciousreasoning/nestegg,kinetiknz/nestegg,kinetiknz/nestegg,SingingTree/nestegg,fallaciousreasoning/nestegg,SingingTree/nestegg,SingingTree/nestegg,kinetiknz/nestegg