📝 docs(changelog): backfill entries

[gaborbernat]

Backfill missing changelog fragments for #617 and #618.

#619 carries its fragment on its own branch.

[codspeed-hq]

Merging this PR will not alter performance

✅ 91 untouched benchmarks
⏩ 18 skipped benchmarks¹

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_{Comparing gaborbernat:docs/changelog-backfill-617-618 (e62c834) with main (ef985c6)}

Footnotes

1. 18 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩