Revised AccessibleValueHandler onChange option documentation.

[pixelzoom]

The documentation for AccessibleValueHandler's onChange option needs some help, see below. There are multiple typos, possibly extra or missing words. I tried to guess what it should be, but bailed. Assigned to the author.

          // Called after any change to valueProperty. Useful for "press and hold" keyboard input. However, be aware
          // that other some devices as switch will only trigger one change per input, and no concept of "press and
          // hold". This function will still be called once per input in those cases.
          onChange: _.noop,

[pixelzoom]

I felt defeated, so I took another run at this. Revised doc in the above commit. @zepumph please review.

[zepumph]

Looks great to me, thanks.