fix slippery rigidbody unity code example

Example: disable rigidbody unity

//This is for Unity (c#)
Rigidbody rb; //For 2D games use 'Rigidbody2D'
  
  void Awake ()
  {
      rb = GetComponent<Rigidbody>();
  }

  // (...)
rb.bodyType = RigidbodyType2D.Static;  // Deactivated
rb.bodyType = RigidbodyType2D./*The type the rigidbody was originally eg. dynamic, kinematic, or static*/; // Activated