Finalize 0.16.7 release notes

[mattwthompson]

I looked through the commits since 0.16.6 and didn't see anything user-facing that was missing

0.16.6...main

I intend to merge this when checks come back green unless there's a quick objection in the mean time

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.86%. Comparing base (ec5ce32) to head (7d5634c).
Report is 1 commits behind head on main.

Additional details and impacted files