Minor copy update: Tracking tutorial page
* Update index.md
* Update index.md
Kept the link and reverted to original wording.
* Update docs/tutorials/tracking/index.md
* Update index.md
# Tracking
-This section contains tutorials for tracking.
+This section contains tutorials showing how to work with object tracking data and how to format it for display as a napari tracks layer.
* [Single cell tracking with napari](cell_tracking)
