(improve doc): add command to run test in parallel (#7189)
(improve doc): add command to run test in parallel (#7189)



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