Type useMessages() hook using IntlMessages

[astralarya]

Is your feature request related to a problem? Please describe.

useMessages() hook does not get proper typing after declaring IntlMessages.

For example:

declare global {
  // Use type safe message keys with `next-intl`
  type IntlMessages = {
    foo: {
      bar: string,
      baz: string,
    }
  }
}

function MyComponent() {
  const messages = useMessages();  // expect this to have type IntlMessages
}

Describe the solution you'd like

I would like the useMessages() hook to respect the type provided by IntlMessages

Describe alternatives you've considered

I've considered casting in place every time I invoke the hook, but this is error prone.

[amannn]

Sounds good, thanks for the report! This will likely make it into the upcoming v4 release: #1489