Update the dsekdocs submodule.

The submodule for the LaTeX templates is 5 commits behind the main repo. We're on commit `ef2eb84` but the latest is `0865a65`.

<img width="2041" height="888" alt="Image" src="https://github.com/user-attachments/assets/adf042f0-1595-475a-b6c0-35410947257d" />