docs: document dependencies required for testing

fix formating.

Author: rouilj

doc/installation.txt

@@ -2214,12 +2214,14 @@ Problems? Testing your Python...
 .. note::
    The ``run_tests.py`` script is not packaged in Roundup's source
    distribution anymore. You should install:
-    * pytest,
-    * requests, and
-    * mock
+
+   * pytest,
+   * requests, and
+   * mock
+
    using your distributions package manger or using pip/pip2/pip3 to
-   install pytest for your python version. See the `administration
-   guide`_ for details.
+   install pytest etc. for your Python version. See the
+   `administration guide`_ for details.
 
    Remember to have a database user 'rounduptest' prepared (with
    password 'rounduptest'). This user