New comment by Chocimier on void-packages repository

https://github.com/void-linux/void-packages/pull/28312#issuecomment-770211177

Comment:
Looks good.
I think now manual need a section explainig all that complexity, something along

    If default do_check do nothing, define one to run upstream tests, if any.
    If tests run over dozen of minutes, put `if XBPS_CHECK_PKGS = full` in do_check, or else make_check=extended.
    Then XBPS_CHECK_PKGS controls what tests to run.