remove nextafter TODO (#1140)

Author: bashbaug

OpenCL_C.txt

@@ -5469,8 +5469,6 @@ endif::cl_khr_fp16[]
     | Returns a quiet NaN.
       The _nancode_ may be placed in the significand of the resulting NaN.
 | gentype *nextafter*(gentype _x_, gentype _y_)
-// TODO shouldn't this be "next representable FP value of the precision of
-// its arguments"? See the OpenCL-Docs issue.
     | Computes the next representable floating-point value
       following _x_ in the direction of _y_.
       Thus, if _y_ is less than _x_, *nextafter*() returns the largest