Update to TextView#didTouchFocusSelect documentation

Bug 6171333

Related to https://android-git.corp.google.com/g/#/c/173335/

Change-Id: Ib4a83b6b0a03579b28d7319c9eb92a4bca09d209

Author: Gilles Debunne

core/java/android/widget/TextView.java

@@ -7490,7 +7490,7 @@ private boolean isTextEditable() {
      * Returns true, only while processing a touch gesture, if the initial
      * touch down event caused focus to move to the text view and as a result
      * its selection changed.  Only valid while processing the touch gesture
-     * of interest.
+     * of interest, in an editable text view.
      */
     public boolean didTouchFocusSelect() {
         return mEditor != null && getEditor().mTouchFocusSelected;