docs: Add spell checking prerequisites for building documentation

Author: JohananOppongAmoateng

docs/contributing.rst

@@ -225,6 +225,19 @@ Prerequisites
 Before building the documentation, ensure that all dependencies are installed
 as described in :ref:`the setup instructions <code>`.
 
+Additionally, to build the documentation with proper spell checking, you need to install:
+
+- **Enchant Library** - This is required by the sphinxcontrib-spelling extension via
+  the pyenchant package. Installation instructions vary by platform:
+
+  - **Windows**: The binary wheel includes a pre-compiled Enchant library.
+  - **macOS**: ``brew install enchant``
+  - **Linux**: Use your distribution's package manager (e.g., ``apt install enchant``)
+  - **FreeBSD**: ``pkg install enchant-2``
+
+  For detailed installation instructions, see the `pyenchant installation documentation
+  <https://pyenchant.github.io/pyenchant/install.html#installing-the-enchant-c-library>`_.
+
 
 
 Using Tox (Cross-Platform)