Revert update development.md

docs/development.md

@@ -341,16 +341,6 @@ If you want to build the documentation locally, this is how you do it:
     ```bash
     $ pipenv install --dev
     ```
-You may need to install the follow extensions manually, if you find that mkdocs is complaining about missing modules, plugins or themes:
-    ```bash
-    $ pip install pymdown-extensions
-    ```
-    ```bash
-    $ pip install mkdocs-material-extensions mkdocs-material
-    ```
-    ```bash
-    $ pip install mkdocs-glightbox
-    ```		
 
 2.  Build the documentation