Update docs dependencies

- sphinx 8.2.3 -> 9.1.0
- sphinx-rtd-them 3.0.2 -> 3.1.0
- myst-parser 4.0.1 -> 5.0.0

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>

Author: acerv

doc/developers/plugins.rst

@@ -165,7 +165,7 @@ Let's suppose we have a ``$HOME/plugins`` folder where we placed our
 ``EmbeddedSUT`` implementation and its scripts. Then we can run ``syscalls``
 testing suite with kirk as following:
 
-.. code-block:: python
+.. code-block:: bash
 
     kirk --plugins $HOME/plugins \
         --sut embedded \