Update Markdown formatting for Prettier 3.4

Prettier 3.4 removes extra spaces after unordered list line prefixes.
https://prettier.io/blog/2024/11/26/3.4.0#markdown

Note that Prettier 3.4 exhibits problematic behavior when formatting
admonitions that are nested within unordered lists. Prettier ignore
comments (`<!-- prettier-ignore -->`) have been added where necessary
to prevent this problematic behavior.
prettier/prettier#16929 (comment)

.github/workflows/ci.yml

@@ -421,7 +421,7 @@ jobs:
           sed -Ei "$ESCAPE_DUNDERS" CHANGELOG.md
           sed -Ei "$ESCAPE_DUNDERS" docs/changelog.md
       - name: Format changelog with Prettier
-        run: npx -s -y prettier@'^3' --write CHANGELOG.md docs/changelog.md
+        run: npx -s -y prettier@'^3.4' --write CHANGELOG.md docs/changelog.md
       - name: Create pull request with updated changelog
         uses: peter-evans/create-pull-request@v6
         with: