South Korean President Yoon Suk Yeol urged ever more strengthening of the U.S.-led security alliance against nuclear-armed North Korea on Thursday, drawing cheers from Congress as he saluted the "great American heroes" who helped preserve his country's democracy in the Korean War. Democratic and Republicans lawmakers rose to their feet again and again to applaud during Yoon's address to a joint meeting of the House and Senate, in a speech that stressed security cooperation at a time of increased tension with both North Korea and China. Yoon also cited U.S.-Korean high-tech trade ties creating thousands of jobs in the United…