Deploy on Vercel: add instructions to explicitly run `npx prisma generate` on Vercel.

[tanberry]

Typically, our deploy operation will trigger npx prisma generate behind the scenes, using a post-install hook. However, Vercel caches dependencies, so the hook doesn't get called on re-deploys.

Solution/workaround is to explicitly run npx prisma generate when deploying to Vercel. @sabinadams or @millsp can you add a bit of detail in a comment below about when exactly in the deployment workflow does the user run this command?

Impacted Docs (there might be others): https://www.prisma.io/docs/guides/deployment/deployment-guides/deploying-to-vercel

There is a Note in this topic that says: "Note: The build step defined in package.json as the vercel-build script, will run prisma generate && prisma migrate deploy && next build to generate Prisma Client, apply migrations, and build the Next.js project."

This note needs to be edited....