Warren Buffett has been selling a lot of stock, and that revelation is inducing his many admirers to follow suit. His Omaha, Nebraska-based conglomerate, Berkshire Hathaway Inc., reported Saturday that it reduced several positions and slashed its stake in top-holding Apple Inc., a sign to some in markets that the “Oracle of Omaha” was bracing for deep stock-market declines. The intended message wasn’t actually as clear-cut as meets the eye, but that nuance might not matter given........