Unify the `output` value of `generator` to `./generated/prisma`

[jy-joung-bitor]

I saw this document because of solving prisma/prisma#28279. There's a code like this:

npm add db@./src/generated/client

And I commanded according to above:

npm add db@./generated/client

But I faced an error because I configured the generater's output to ../generated/prisma, not ../src/generated/client. Moreover, there're many sentences that are different with a default value(generated/prisma).

Do you please accept the change to one configuration for avoiding misconsideration?