Add missing PRs to release notes (#6949)

* Add missing PRs to release notes

* Add recent output from generate_release_notes.py

See c774f12,
ran on 2023-05-31 19:25 UTC.

* Add paragraph on unified random API

* Fix extra space

* Move lazy loading PRs to Performance section

* Remove v in front of version spec

* Add final PRs

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Co-authored-by: Lars Grüter <lagru@mailbox.org>