Update docs

docs_Adding_docs.html

@@ -112,7 +112,7 @@
 </ol>
 <h1><a class="anchor" id="docs_Adding_docs__Building_documentation_locally"></a>
 Building documentation locally</h1>
-<p>The documentation can be built locally by running the following commands from the root directory: </p><div class="fragment"><div class="line">cmake -DGYSELALIBXX_COMPILE_SOURCE=OFF -DBUILD_DOCUMENTATION=1 -B build-docs .</div>
+<p>The documentation can be built locally by running the following commands from the root directory: </p><div class="fragment"><div class="line">cmake -DGYSELALIBXX_COMPILE_SOURCE=OFF -DGYSELALIBXX_BUILD_DOCUMENTATION=1 -B build-docs .</div>
 <div class="line">cmake --build build-docs</div>
 </div><!-- fragment --><p> The option <code>-DGYSELALIBXX_COMPILE_SOURCE=OFF</code> ensures that the C++ code is not built, thereby avoiding the need to have all the C++ dependencies installed on your system. If this option is not used then <code>make docs</code> should be used to build only the documentation.</p>
 <p>In order to view the docs the file <code>build-docs/docs/html/index.html</code> should be opened in a browser (e.g. Firefox).</p>