Fix recent regression in implicit search (don't include inPackagePrefix in ImplicitInfo equality)

[lrytz]

This lead to some implicit inference failures in the community build.

scala/community-build#1710 (comment)

Follow-up for #10621

[som-snytt]

I was looking forward to spending the morning debugging that issue, but instead I'll spend it understanding this tweak.

[lrytz]

[lrytz]

https://github.com/etorreborre/specs2/blob/c9049ff7b80d67203caa2801676296f1bc3eed19/shapeless/src/main/scala/org/specs2/shapeless/Projection.scala#L51

https://github.com/milessabin/shapeless/blob/c67ef298aed6727b1290357b9da252b31f441c7f/core/shared/src/main/scala/shapeless/package.scala#L43

Not sure what to make of it. The implicit was found once in the package, once in the package object. Maybe because the corresponding trait trait =:!= is also defined in the package object.

[SethTisue]

I'll do a local, partial community build run shortly to see how many of the other failing projects this progresses.

[SethTisue]

This fixed all 5 failing projects. We'll have full results tomorrow.

[SethTisue]

Whole community build is green.