Update CHANGELOG.md for 9.2.0

CHANGELOG.md

changelogs/unreleased/12910-personal-snippet-prep-2.yml

changelogs/unreleased/12910-personal-snippets-notes-show.yml

changelogs/unreleased/12910-personal-snippets-notes.yml

changelogs/unreleased/12910-uploader-pers-snippet.yml

changelogs/unreleased/1440-db-backup-ssl-support.yml

changelogs/unreleased/17361-redirect-renamed-paths.yml

changelogs/unreleased/19364-webhook-edit.yml

changelogs/unreleased/20378-natural-sort-issue-numbers.yml

...gelogs/unreleased/21683-show-created-group-name-flash.yml

...s/unreleased/22714-update-all-instances-of-fa-refresh.yml

...stency-different-files-views-find-file-button-missing.yml

.../unreleased/23751-add-contribution-graph-key-tooltips.yml

changelogs/unreleased/24883-build-failure-summary-page.yml

changelogs/unreleased/25226-realtime-pipelines-fe.yml

changelogs/unreleased/26208-animate-drodowns.yml

changelogs/unreleased/26437-closed-by.yml

changelogs/unreleased/26488-target-disabled-mr.yml

changelogs/unreleased/26509-show-update-time.yml

changelogs/unreleased/26585-remove-readme-view-caching.yml