Add note to docs for i18n and next export (#19321)
Add note to docs for i18n and next export (#19321)

This adds a note about current `i18n` support and `next export` since it is not currently supported as was mentioned in the [initial RFC](https://github.com/vercel/next.js/discussions/17078)

x-ref: https://github.com/vercel/next.js/issues/18318

azukaru/next.js,zeit/next.js,JeromeFitz/next.js,flybayer/next.js,JeromeFitz/next.js,azukaru/next.js,zeit/next.js,JeromeFitz/next.js,azukaru/next.js,JeromeFitz/next.js,zeit/next.js,azukaru/next.js,flybayer/next.js,flybayer/next.js,flybayer/next.js