bug workaround when saving an event handler

Due to https://github.com/fish-shell/fish-shell/issues/845 the functions handling events are not activated upon load. Funcsave of the event handlers doesn't lead to proper results and should be avoided.
What about:

You can define your function in ``.config/fish/config.fish`` or put it anywhere Fish will see it before it needs to run. When using  ``funcsave`` note that  functions are not listening to events after Fish startup until loaded by ``functions myfunc``.