Update docs to match behaviour
Occasionally, you may want to use pip to manage a Python installation other than
the one pip is installed into. In this case, you can use the `--python` option
-to specify the interpreter you want to manage. This option can take one of three
+to specify the interpreter you want to manage. This option can take one of two
values:
1. The path to a Python executable.
2. The path to a virtual environment.
-3. Either "py" or "python", referring to the currently active Python interpreter.
-In all 3 cases, pip will run exactly as if it had been invoked from that Python
+In both cases, pip will run exactly as if it had been invoked from that Python
environment.
One example of where this might be useful is to manage a virtual environment
