Update doc/en/reference/reference.rst

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <[email protected]>

Author: mtelka

doc/en/reference/reference.rst

@@ -1153,7 +1153,9 @@ specified plugins will be loaded.
 
 .. envvar:: PYTEST_PLUGINS
 
-Contains comma-separated list of modules or entry points that should be loaded as plugins:
+Contains comma-separated list of :term:`importable modules <Module>`
+or :ref:`entry point names <pip-installable plugins>` that should be
+loaded as plugins:
 
 .. code-block:: bash