Document Controlled vs Uncontrolled Component Design pattern

pursuant to this discussion https://twitter.com/dan_abramov/status/1001943857096003584

all react components can be:

• controlled (no internal state)
• uncontrolled (internal state)
• mixed (uncontrolled by default, unless some props are passed to make it controlled)

the current docs on controlled vs uncontrolled: https://reactjs.org/docs/uncontrolled-components.html focus entirely on forms, but this design pattern applies to -all- components. we should document this.

questions

1. What else should we say in the docs?
2. do we want to tell people that they can do "mixed control" or do we leave that for people to discover for themselves?
3. is this the same page as https://reactjs.org/docs/uncontrolled-components.html or is it a separate page?

Inizia dalla documentazione esistente di uncontrolled-components.html e dalla discussione collegata. Determina se i controlled, uncontrolled e mixed component patterns debbano appartenere a questa pagina o a una pagina separata, e stabilisci quali indicazioni debba fornire la documentazione. Il lavoro è completo quando la documentazione selezionata copre chiaramente il pattern oltre i form e risponde alle domande aperte sull'ambito.