* fix: allow preprocess to return a promise * fix: types * chore: format * chore: changelog * Update changelog_unreleased/api/15123.md Co-authored-by: fisker Cheung <lionkay@gmail.com> * apply changes * Update 15123.md * Update 15123.md * Simplify changelog --------- Co-authored-by: fisker Cheung <lionkay@gmail.com>