Switch to running src/pip now pypa#5481 is merged

docs/html/development/getting-started.rst

@@ -21,26 +21,11 @@ Running pip From Source Tree
 ----------------------------
 
 To run the pip executable from your source tree using the currently active
-virtualenv (or conda environment) during development, run from a ``tox``
-environment, after having run the tests at least once:
+virtualenv during development, run pip from the ``src`` directory:
 
 .. code-block:: console
 
-    $ .tox/py36/bin/pip --version
-
-.. note::
-    You need to do run ``tox -e py36 --recreate`` after any changes to your
-    virtualenv if using pip like this.
-
-.. note::
-    You can use any other tox environment instead of ``py36``.
-
-.. note::
-    ``tox -e py36 --notest`` can be used, if running tests is not a concern.
-
-.. note::
-    An easier alternative is running ``python src/pip``, however there are
-    `edge cases <https://github.com/pypa/pip/pull/5841>`_ that may not work.
+    $ python src/pip --version
 
 Running Tests
 -------------