[RenderScript] Update the documentation of Script.LaunchOptions

Bug: 26916665

  - Add description of the endArg.
  - Update the example.
  - Update the incorrect description.

Change-Id: Idd07db5d790e2d6462fff9cb580115ec45cfd4f0
(cherry picked from commit 53fdcfbe63c1d4b2f1cbee6e72a6dd13f41dc1bc)
1 file changed