Update documentation for repository last and second methods

[davydovanton]

Reference to hanami/model#380

/cc @hanami/documentation @cllns @jodosha

[cllns]

Thanks for remembering to do this @davydovanton <3

I committed some changes to this branch. I think they help explain the rationale behind recommending one vs first.

But I don't think this should be merged now:

• someone else should check my changes for accuracy, and
• we should add note about how first and last are different (returning Hash vs entity). I feel like that was the impetus behind this change, and we don't directly address it. Instead, we tell people how to avoid it.

[davydovanton]

@cllns

[AlfonsoUceda]

@cllns @davydovanton good work ;)

The documentation is fine for me but as @cllns said:

we should add note about how first and last are different (returning Hash vs entity). I feel like that was the impetus behind this change, and we don't directly address it. Instead, we tell people how to avoid it.

This would be perfect :)

[AlfonsoUceda]

@cllns @davydovanton is there a chance to finish this?