Make Listening for Events section inclusive of custom controllers

docs/introduction/interactions-and-controllers.md

@@ -499,14 +499,15 @@ For advanced examples on real applications, see the [paint-controls component
 for A-Painter][a-painter] or the [shoot-controls component for
 A-Blast][a-blast].
 
-## Listening for Button and Axis Events
-
-Controllers have many buttons and emit many events. For each button, every time
-a button is pressed down, released, or for some cases, even touched. And for
-each axis (e.g., trackpad, thumbstick), an event is emitted every time it is
-touched. To handle buttons, look for the event name in the respective
-controller component documentation pages at the event tables, then register
-event handlers how we want:
+## Listening for Controller Events
+
+The events emitted by the A-Frame and vendor specific controllers (e.g Quest,
+Index...) build on the base level events emitted by the
+[tracked-controls component]((#tracked-controls-component)) to the specific
+events of each controller. To handle these events, we look for the event name
+in the controller component's documentation pages at the event tables, then
+register event handlers how we want. Here are the events emitted by A-Frame's
+controller components:
 
 - [daydream-controls events](../components/daydream-controls.md#events)
 - [gearvr-controls events](../components/gearvr-controls.md#events)