mercurial/help/common.txt

run-tests: set attributes in sorted order

Python 3.8 preserves insertion order in serialized output
(https://bugs.python.org/issue34160). Older Pythons serialized
in sorted order.

Let's make insertion order sorted so behavior is consistent across
Python versions.

Differential Revision: https://phab.mercurial-scm.org/D5831

.. Common link and substitution definitions.

.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html