Remove docs for removed a11y gesture methods.

 * Accessibility services with the

 * {@link android.R.styleable#AccessibilityService_canPerformGestures} property can dispatch

 * gestures. This class describes those gestures. Gestures are made up of one or more strokes.

 * Gestures are immutable; use the {@code create} methods to get common gesture, or a

 * {@code Builder} to create a new one.

 * Gestures are immutable once built.

 * <p>

 * Spatial dimensions throughout are in screen pixels. Time is measured in milliseconds.

 */