fix a comment

Dependencies

• [2] JCSLDGAH beginnings of support for multiple shapes
• [3] 6LJZN727 handle chords
• [4] OTIBCAUJ love2d scaffold

Change contents

• replacement in main.lua at line 21
  [2.547]→[2.547:643](∅→∅)
  − -- cx,cy, r for mode 'circle'

  − -- pc, r for mode 'circle'

  − -- pc, r, s, e for mode 'arc'
  [2.547]

  [2.643]
  + -- center, radius for mode 'circle'

  + -- center, radius, start_angle, end_angle for mode 'arc'