Fix divider hints

Resolves T1999. The divider was not putting things on the correct lines, leading to nonsensical hints.

Test Plan: Click through all the hints for at least one problem in each of converting_fractions_to_decimals, converting_fractions_to_decimals, dividing_decimals_0.5, dividing_decimals_3, dividing_decimals_4, dividing_rational_numbers, dividing_rational_numbers, dividing_rational_numbers, dividing_rational_numbers, division_1.5, division_2, division_3, and division_4

Auditors: peter, joel