Unify how optional values are marked in docstings

* No longer means 'has default value'. Removed where it meant that.
* `Optional[datatype]` is now used instead of `datatype, optional`
* Fixed a handful of incorrect type annotations

examples/count_people_in_zone/inference_example.py

@@ -75,7 +75,7 @@ def detect(
         frame (np.ndarray): The frame to process, expected to be a NumPy array.
         model (RoboflowInferenceModel): The Inference model used for processing the
             frame.
-        confidence_threshold (float, optional): The confidence threshold for filtering
+        confidence_threshold (float): The confidence threshold for filtering
             detections. Default is 0.5.
 
     Returns:

examples/count_people_in_zone/ultralytics_example.py

@@ -72,7 +72,7 @@ def detect(
     Args:
         frame (np.ndarray): The frame to process, expected to be a NumPy array.
         model (YOLO): The YOLO model used for processing the frame.
-        confidence_threshold (float, optional): The confidence threshold for filtering
+        confidence_threshold (float): The confidence threshold for filtering
             detections. Default is 0.5.
 
     Returns:

examples/time_in_zone/utils/timers.py

@@ -22,7 +22,7 @@ class FPSBasedTimer:
         """Initializes the FPSBasedTimer with the specified frames per second rate.
 
         Args:
-            fps (int, optional): The frame rate of the video stream. Defaults to 30.
+            fps (int): The frame rate of the video stream. Defaults to 30.
         """
         self.fps = fps
         self.frame_id = 0