[5.0.0] Is Data API still unimplemented?

[ryantheleach]

https://docs.spongepowered.org/master/en/plugin/data/index.html Has a warning about the Data API being somewhat unimplemented.

I believe it's close to being untrue, so created an issue to track it so it's not forgotten.

[Inscrutable]

Things have evolved somewhat, but we still lack decent docs for Data (Issue #335 has stalled, as Saladoc is on extended hiatus). I agree it needs updating. Who understands it enough to have a go at finishing this?

[Inscrutable]

There are 16 items left unfinished on the checklist at SpongePowered/Sponge#8 so the warning is still somewhat relevant. We can amend it a bit, but it would be preferable to have the list finished and just drop the warning.