How do I add comments in-line to commands that do not have a dialog box?

With the Script Editor open, highlight a line in the macro script and click on the Insert Comments button. This option opens a Comments edit box. Type any comments about the line in the script in the this field and click OK to insert the comments next to the command listed in the script.

The Insert Comments button is on the right side of the script editor. Hover over the icons there and the title of the icon will be displayed.