Remove docs for removed a11y gesture methods.

Bug: 27364143
Change-Id: I853090b7bd27cbb887e49ed6755179b596fa6a74
diff --git a/core/java/android/accessibilityservice/GestureDescription.java b/core/java/android/accessibilityservice/GestureDescription.java
index 7a0c89b..e18a34d 100644
--- a/core/java/android/accessibilityservice/GestureDescription.java
+++ b/core/java/android/accessibilityservice/GestureDescription.java
@@ -36,8 +36,7 @@
  * 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.
  */