docs: fix Foundation 6 CLI uninstallation note phrasing
docs: fix Foundation 6 CLI uninstallation note phrasing

colin-marshall/foundation-sites,denisahac/foundation-sites,colin-marshall/foundation-sites,zurb/foundation-sites,denisahac/foundation-sites,denisahac/foundation-sites,abdullahsalem/foundation-sites,zurb/foundation,abdullahsalem/foundation-sites,zurb/foundation-sites,DaSchTour/foundation-sites,DaSchTour/foundation-sites,zurb/foundation,zurb/foundation,abdullahsalem/foundation-sites,colin-marshall/foundation-sites,zurb/foundation-sites