President Biden and former President Donald J. Trump on Tuesday secured the delegates necessary to clinch their parties’ presidential nominations, according to The Associated Press, cementing a general election rematch in November months in the making.Both men and their campaigns have long anticipated this moment. Mr. Biden faced only token opposition in the Democratic primary, as is typical for a sitting president, while Mr. Trump had been his party’s dominant front-runner for months.Their November collision began to look even more likely after Mr. Trump scored a decisive win in Iowa…