Financial markets finished the week on a high note after Federal Reserve Chair Jerome Powell stood his ground against President Trump in a rare joint appearance by the two men Thursday. The S&P 500 finished 0.4 percent up, and the Dow Jones Industrial Average finished up 208 points or 0.47 percent. The tech-heavy Nasdaq Composite gained about a quarter of percent to close above 21,108. ... Friday’s gains followed a confrontation between Trump and Powell on Thursday in which Powell repelled an attack from Trump — this time not on social media but on television. The exchange took place at...