COLUMBIA, S.C. — Attorneys for Alex Murdaugh on Thursday filed a notice to appeal his convictions for the murder of his wife and son along with his life sentence.The trial in rural South Carolina lasted six weeks and included more than 75 witnesses, but culminated in a jury taking less than three hours to find the 54-year-old Murdaugh guilty last week.Murdaugh called 911 on the evening of June 7, 2021, saying he found his son and wife dead when he returned home from a one-hour visit with his mother, who has dementia …