DOCS: Fix code-block (pydata#11228)

Author: jsignell

doc/contribute/contributing.rst

@@ -241,7 +241,7 @@ You can either run pre-commit manually via Pixi as described above, or set up gi
 
 This is done by:
 
-.. code-block:: sh
+.. code-block:: shell
 
     pixi shell -e pre-commit # enter the pre-commit environment
     pre-commit install # install the git hooks