Update installation instructions.

docs/source/user_guide/installation.rst

@@ -12,18 +12,18 @@ You can install them with::
 
     pip install gama[OPTIONAL]
 
-where `OPTIONAL` is one of:
+where `OPTIONAL` is one or more (comma separated):
 
  - `vis`: allows you to use the prototype dash app to visualize optimization traces.
  - `dev`: sets up all required dependencies for development of GAMA.
- - `all`: all of the above.
+ - `doc`: sets up all required dependencies for building documentation of GAMA.
 
 To see exactly what dependencies will be installed, see `setup.py <https://github.com/openml-labs/gama/blob/master/setup.py>`_.
-If you plan on developing GAMA, cloning the repository and installing locally is advised::
+If you plan on developing GAMA, cloning the repository and installing locally with test and doc dependencies is advised::
 
     git clone https://github.com/PGijsbers/gama.git
     cd gama
-    pip install -e .[all]
+    pip install -e ".[doc,test]"
 
 This installation will refer to your local GAMA files.
 Changes to the code directly affect the installed GAMA package without requiring a reinstall.