Converts this quaternion to one with the same orientation but with a magnitude of 1.
When normalized, a quaternion keeps the same orientation but its magnitude is 1.0.
Note that this method will change the current quaternion. If you
want to keep the current quaternion unchanged, use the normalized property instead.
If this quaternion is too small to be normalized it will be set to Quaternion.identity.
另请参阅：normalized 变量。