SPRINGFIELD — A handful of Illinois lawmakers have vowed to study Bitcoin, the digital currency that’s skyrocketed in price and popularity, as well as the technology that makes it possible.The Illinois House has created a small committee on Distributed Ledgers and Cryptocurrency in advance of its spring session, which begins at the end of this month.It follows a larger task force, which includes the governor’s office, the state’s financial regulation department and its innovation and technology …