SPRINGFIELD — A 30-day paid-leave benefit for teachers who give birth doesn’t guarantee the right to hold those days for a subsequent school year, the Illinois Supreme Court ruled Thursday.The justices were asked whether a provision in the Illinois School Code, which gives teachers the ability to claim at least three days for personal illness and 30 days for the birth of a child, accounts for summer break in how teachers can use those days.Wood Dale District 7 third-grade teacher Margaret Dynak gave birth two days before …