doc: fix spelling issue in _preparation_next_release.md
@@ -390,7 +390,7 @@ This section keeps you up-to-date with the multi-language support provided by El
- Add tutorial for manual installation from the AUR on Arch Linux _(@Bujuhu)_
- <<TODO>>
-- Add markdown shell recorder validation to install.webui.md _(@deoknats861)_
+- Add Markdown shell recorder validation to install.webui.md _(@deoknats861)_
- <<TODO>>
- <<TODO>>
- <<TODO>>
