Improve installation docs

Author: humitos

docs/installation.rst

@@ -32,4 +32,9 @@ To do this, add this extension to your Sphinx's extensions in the ``conf.py`` fi
 
 
 After installing the package and adding the extension in the ``conf.py`` file,
-all the ``:ref:`` roles will show a tooltip when hovering with the mouse.
+you can use ``:hoverxref:`` role to show tooltip when hovering with the mouse.
+
+If you prefer to apply this behavior to *all* your ``:ref:`` in your documentation,
+you can use the config :confval:`hoverxref_auto_ref`.
+
+See :ref:`usage:usage` for more use cases and :ref:`configuration:configuration` for a full list of available configs.