Update DXIL.rst (#267)

Fixed Htan behavior for +/- INF.

docs/DXIL.rst

@@ -2376,7 +2376,7 @@ Returns the hyperbolic tangent of the specified value.
 +----------+------+------------+---------+----+----+---------+------------+------+-----+
 | src      | -inf | -F         | -denorm | -0 | +0 | +denorm | +F         | +inf | NaN |
 +----------+------+------------+---------+----+----+---------+------------+------+-----+
-| htan(src)|  NaN | -F         |       0 |  0 |  0 |       0 | +F         |  NaN | NaN |
+| htan(src)| -1   | -F         |       0 |  0 |  0 |       0 | +F         | +1   | NaN |
 +----------+------+------------+---------+----+----+---------+------------+------+-----+
 
 IMad