[docs] [issue18576] Document test.support.script_helper

Nick Coghlan added the comment: script_helper was moved to the test.support package in issue 9517, so this issue is just about adding the docs now. ---------- dependencies: +Make test.script_helper more comprehensive, and use it in the test suite -Refactor the test_runpy walk_package support code into a common location title: Rename and document test.script_helper as test.support.script_helper -> Document test.support.script_helper versions: +Python 3.5 -Python 3.4 _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue18576> _______________________________________