docs: Added documentation on how to generate docs locally (#2220)

* docs: added documentation on how to generate docs locally

Author: okotdaniel

docs/changes.rst

@@ -13,6 +13,8 @@ Pending
   class instance, regardless if any data was generated.
 * Fixed selenium tests for CI by using psycopg for Python 3.13 runs.
 * Added ``CommunityPanel`` containing links to documentation and resources.
+* Added how to generate the documentation locally to the contributing
+  documentation.
 
 6.0.0 (2025-07-22)
 ------------------

docs/contributing.rst

@@ -12,6 +12,8 @@ You can report bugs and request features in the `bug tracker
 
 Please search the existing database for duplicates before filing an issue.
 
+.. _code:
+
 Code
 ----
 
@@ -207,3 +209,60 @@ The release itself requires the following steps:
 #. **After the publishing completed** edit the automatically created GitHub
    release to include the release notes (you may use GitHub's "Generate release
    notes" button for this).
+
+
+Building the documentation locally
+----------------------------------
+
+The project's documentation is built using `Sphinx <https://www.sphinx-doc.org>`_.
+You can generate it locally to preview your changes before submitting a pull
+request.
+
+
+Prerequisites
+--------------
+
+Before building the documentation, ensure that all dependencies are installed
+as described in :ref:`the setup instructions <code>`.
+
+
+
+Using Tox (Cross-Platform)
+------------------------------------
+
+To build the documentation using Tox, run from the project root:
+
+.. code-block:: bash
+
+    tox -e docs -- html
+
+This will generate the HTML files in ``docs/_build/html/``.
+
+You can then open the documentation in your browser:
+
+- **Linux:** ``xdg-open docs/_build/html/index.html``
+- **macOS:** ``open docs/_build/html/index.html``
+- **Windows:** ``start docs\_build\html\index.html``
+
+*Tox automatically installs the necessary dependencies, so you don’t need
+to activate a virtual environment manually.*
+
+
+Troubleshooting
+----------------
+
+
+If you encounter an error about a missing dependency such as
+``sphinx-build: command not found``, ensure that your virtual environment is
+activated and all dependencies are installed:
+
+.. code-block:: bash
+
+    pip install -r requirements_dev.txt
+
+Alternatively, you can build the documentation using Tox, which automatically
+handles dependencies and environment setup:
+
+.. code-block:: bash
+
+    tox -e docs -- html