Add `findFirst` to list of batchable functions

[cunisia]

Apparently, findFirst calls are also batched when occurring in the same tick and having the same where and include parameters. Wouldn't it be good to update the Query Optimization article so that users know about that ?

(I only learnt about it because I wanted to check if batching findMany calls was a soon to come feature. So I searched for the corresponding github issue which fortunately included a link to the issue where findFirst got batched)

[janpio]

I am not sure this is actually true. findOne (now called findUnique) and findFirst are different things.

[ankur-arch]

Hey @cunisia 👋 thanks for opening this issue! I'm aware that it has been around for a while but we're only now getting to a major cleanup of the docs repo, so apologies for the delay. I'm closing this issue as it seems to be outdated, but please feel free to open other issues in the future if you notice anything that can be improved in the Prisma docs 🙏