If there was one piece of advice the boss of hedge fund Citadel LLC would give to the Federal Reserve, it would be to stop talking so much. Every time Fed chair Jay Powell opens his mouth to discuss all the progress the central bank has achieved cooling off last year’s red-hot inflation, he may actually just be making his own job harder by confusing investors with different messages. Citadel founder Ken Griffin, the most successful hedge fund manager on Wall Street last year, urged Powell to stick to just one key talking point so as to anchor inflation expectations...