Update, 11 p.m.: Brian Williams apologized on-air tonight for claiming that he was in a helicopter hit by an RPG in Iraq, but the version of events he gives in his apology is vague in a way that avoids addressing the main accusation of the soldiers quoted in Stars and Stripes questioning his accounts of events. Those soldiers, in Stars and Stripes' telling, say that not only was Williams not in a helicopter that was hit by an RPG, but that he was nowhere near the helicopters that were actually fired upon. Said Williams tonight: "I made a mistake in...