update the intro to p5.strands file formatting

[Piyushrathoree]

fixes #1076

[davepagurek]

Hi! I think there are more cases present in the tutorial, e.g. the instancing example screenshotted in the issue. Maybe try doing a find-and-replace in the file for the tab character?

[Piyushrathoree]

Hi! I think there are more cases present in the tutorial, e.g. the instancing example screenshotted in the issue. Maybe try doing a find-and-replace in the file for the tab character?

done