As the image shows, only tab twice to align with the word above (step 1.), then move up a line and tab to move both into place (step 2.) Finish the alignment by tabbing the top line into place (step 3.).
Remember too, that Revit will cruelly “adjust” your text when it goes into edit text mode, meaning that the justification will be different than when you first clicked on it. But it will remember when you exit. So as long as you like what you see on screen when you are done editing, that is what you will see when you exit the edit mode.