Document not to use propagateCreateError: false

[rjmackay]

Environment

ALL

Missing / erroneus documentation

There are multiple comments on github issues directing users never to use propagateCreateError: false in the tarn pool config (like:
#3447 (comment)) but there is not mention of it in the docs.

Could this be included in documentation here? https://knexjs.org/guide/#pool

Ideally, with information on why this shouldn't be enabled.

I would be happy to PR docs, but I don't fully understand the reason why this shouldn't be added myself. From a naive look at the tarn docs it seems like you would want to enable this so failed attempts to connect get retried.