message: fixed typo in models.md
diff: @@ -125,7 +125,7 @@ This allows for a flexible implementation of a vareity of linear and non-linear
  ### Single Track Model
  -By far the most used dynamic model in BARK, it the single-track model.
  +By far the most used dynamic model in BARK is the single-track model.
  It represents a simplified bicycle vehicle-model.
  The `SingleTrackModel` class overloads the `StateSpaceModel` function and is given by:
  