bug: fix typo on line 6 of SpaceTimeAStar.py

[spnsingh]

Reference issue

N/A

What does this implement/fix?

Fixed a tiny typo in the comments of the Space-time A* algorithm code. On line 6 "respescting" --> "respecting"

Additional information

N/A

CheckList

• Did you add an unittest for your new example or defect fix?
  N/A
• Did you add documents for your new example?
  N/A
• All CIs are green? (You can check it after submitting)
  N/A

[AtsushiSakai]

Thanks!!