[GRASS-git] [OSGeo/grass-website] c668a4: Update mac.en.md

[Michael Barton]

  Branch: refs/heads/cmbarton-update-download-links
  Home:   https://github.com/OSGeo/grass-website
  Commit: c668a4ddcecf085025386ec3e82b1d767f8c65e2
      https://github.com/OSGeo/grass-website/commit/c668a4ddcecf085025386ec3e82b1d767f8c65e2
  Author: Michael Barton <cmbarton at users.noreply.github.com>
  Date:   2023-09-19 (Tue, 19 Sep 2023)

  Changed paths:
    M content/download/mac.en.md

  Log Message:
  -----------
  Update mac.en.md

further corrections to link to new GRASS4Mac site