Spirit Airlines lenders have committed another $300 million in financing for the Dania Beach-based airline — money intended to fuel the discount carrier’s operations after it departs from bankruptcy court. The airline “has secured a commitment from certain of its prepetition debtholders” to lend more money for working capital and “other corporate needs of the company” after it exits Chapter 11 bankruptcy proceedings, management said in a filing late last week with the Securities and Exchange Commission. The commitments came as Spirit put the finishing touches on a cost-cutting program that has resulted in workforce cutbacks that affect several hundred pilots and 200 support workers.