Diff looks great - minimal, and looks correct. As a checklist for these very standard ones:

• Applies the _transition_to_rng decorator
  • Passes correct old_name (``"seed"`, in this case) to decorator factory
  • Passes correct position_num (2, in this case) to decorator factory
• replaces old keyword in signature with rng
• replaces documentation of old keyword with final documentation recommended by SPEC 7
• replaces most uses of old keyword in tests / other functions with rng / Generator
• notes remaining uses of old keyword (left to test backward compatibility during transition)
• check that decorate has replaced documentation correctly

If the tests come back happy and docs look good, I'll merge.