No, you don't need to edit your return to show the value of the grocery tax credit.
A refund of state income taxes paid may be taxable in the year you receive the refund (i.e. refund of 2015 state taxes you received in 2016). Any tax credit for your state income taxes is not a refund of state income tax; it is treated as a "payment" applied against your state income tax liability. The state income tax doesn't change (increase or decrease) because of the credit, just the amount you are credited as paying toward your state income tax.