Doc request: Document how you can extend PrismaClient when using event based logging.

[pantharshit00]

You will need to use a generic when doing this which is not clear in first go to beginners so we should document this.

More information here: https://github.com/prisma/prisma/issues/6279#issuecomment-808702894

Example here: https://github.com/prisma/prisma/issues/4746#issuecomment-750949556

[pantharshit00]

Another variant of the same topic: https://github.com/prisma/prisma/issues/6774#issuecomment-876498070

[prithvihv]

@pantharshit00 https://github.com/prisma/prisma/issues/15309#issue-1372169392 might this be related?

[nikelborm]

May be related https://github.com/prisma/prisma/pull/24133