Improve appended toctrees for children

[dvdmc]

🦟 Bug fix

No issue oppened

Summary

When creating a doc file with children, if the user writing forgets to add a break at the end of the file, the toctree is not separated from the text.

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.