ksh's %q prefers quotes; for your example it prints 'text with spaces', and for the article's example, $'This string \'has single\' "and double" quotes and

ksh's %q prefers quotes; for your example it prints 'text with spaces', and for the article's example, $'This string \'has single\' "and double" quotes and a $' vs bash's %q, This\ string\ \'has\ single\'\ \"and\ double\"\ quotes\ and\ a\ \$