Support specifying an occurrence ordinal for things to set/click

[mfulton26]

Examples:

await automator.click.second("Process Payment"); // click 2nd occurrence of "Process Payment"

await automator.set.third("First Name").to("Joyce"); // set 3rd occurrence of "First Name"

await automator.set[0]('Shipping Information').to('2-Day'); // set 1st "Shipping Address"
await automator.set[1]('Shipping Information').to('2-Day'); // set 2nd "Shipping Address"

await automator.set.first('Shipping Information').to('2-Day'); // set 1st "Shipping Address"
await automator.set.second('Shipping Information').to('2-Day'); // set 2nd "Shipping Address"