feat(validation): referentialIntegrity and relationMode attributes cannot be used together

[jkomyno]

Before this PR, the following schema was considered valid:

datasource db {
  provider = "sqlite"
  url = "..."
  relationMode = "prisma" // we take relationMode in priority
  referentialIntegrity = "foreignKeys" // is ignored
}

This PR makes it invalid, as only one attribute between relationMode or referentialIntegrity (or none) should be used.
The validation error is:

The referentialIntegrity and relationMode attributes cannot be used together. Please use only relationMode instead.

Closes prisma/prisma#15735.

[jkomyno]

Follow-up (@Jolg42, @tomhoule): we can probably create a VSCode quick action to:

• remove referentialIntegrity in favor of relationMode if both attributes exist
• rename referentialIntegrity into relationMode if only the referentialIntegrity attribute exists

However, I'd need a couple of directions to achieve that.

[tomhoule]

looks good to me 👍

[janpio]

Did this quick action suggestion get created as an issue @jkomyno? If not, please do so or this will be forgotten.

[jkomyno]

Tracked the quick action suggestion here: prisma/language-tools#1276