document pip commands from pipenv

docs/index.rst

@@ -109,7 +109,7 @@ Other Commands
 
 - ``graph`` will show you a dependency graph, of your installed dependencies.
 - ``shell`` will spawn a shell with the virtualenv activated.
-- ``run`` will run a given command from the virtualenv, with any arguments forwarded (e.g. ``$ pipenv run python``).
+- ``run`` will run a given command from the virtualenv, with any arguments forwarded (e.g. ``$ pipenv run python``). Notably, ``run`` can be used to invoke various pip utility commands, as in ``$ pipenv run pip show requests``.
 - ``check`` checks for security vulnerabilities and asserts that PEP 508 requirements are being met by the current environment.