[Docs]: Change "messages" variable name to "timeZone"

[IlyaMinarov]

Link to page

https://next-intl-docs.vercel.app/docs/usage/configuration#time-zone

Describe the problem

From the page:

// Regular components
import {useTimeZone} from 'next-intl';
const messages = useTimeZone();
 
// Async Server Components
import {getTimeZone} from 'next-intl/server';
const timeZone = await getTimeZone();

For consistency the above should be:
const timeZone = useTimeZone();

[amannn]

Of course, yes—thanks for noticing! 😊