R1:27626e6d472d

Document a policy about fishing expeditions

Summary:
Tighten the Phabricator support policy from "we will help with literally anything for free" to "we will help with anything for free, except unreproducible fishing expeditions".

This is not the right policy in the long term (in some form, I expect the level of free support will decrease, and, e.g., I won't be offering to drive to your place and fix your stuff), but this class of issue is by far the worst and most pressing and I want to stop dealing with…