[comp-scroll-anim] Adjusted use case wording.

Author: ianvollick

composited-scrolling-and-animation/UseCases.md

@@ -46,7 +46,7 @@ Gesture Recognition
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 - With the ability to process input on the compositor thread, we would have the ability to write custom gesture recognition.
 
-Location Tracking
+Element Location Tracking
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 - It would be nice to keep track of the location of an element with respect to another element (in particular, a scroll clip), to get an asynchronous, as-accurate-as-possible set of records of the element's location history.