Fix pip download example in usage
Fix pip download example in usage

pfmoore/pip,sbidoul/pip,rouge8/pip,xavfernandez/pip,xavfernandez/pip,pradyunsg/pip,pradyunsg/pip,pypa/pip,pypa/pip,rouge8/pip,xavfernandez/pip,sbidoul/pip,rouge8/pip,pfmoore/pip