updated tuto init

[PierreMartinon]

Notes:

• init=() and init=nothing are both accepted and equivalent to not passing the argument.
• I removed the unsupported keywords Private=false in the index blocks (gave warnings)

[ocots]

Private = false is important and it was supported. Do know what replace this?

[PierreMartinon]

Private = false is important and it was supported. Do know what replace this?

More precisely, Private is used in autodocs blocks (I left them there), not index blocks (these gave unsupported warnings) ;-) https://documenter.juliadocs.org/stable/man/syntax/#@autodocs-block https://documenter.juliadocs.org/stable/man/syntax/#@index-block

[PierreMartinon]

Updated actions got rid of the old nodes warnings.

@ocots I think I have finished this one, you can merge when ready