There is no note. In the HSA section TurboTax simply allows you to indicate amounts that were omitted from your W-2 so that they will appear on Form 8889 as employer contributions.
Note that in addition to including the contribution with code W in box 12 of your W-2, the employer should not have included this amount in box 1 of your W-2. (If the employer included this amount in box 1, you could simply indicate that the amount was a personal contribution and receive a deduction for the contribution.)
