When Judge Aileen M. Cannon presides over a hearing on Friday in former President Donald J. Trump’s classified documents case, she will spend the day considering well-trod arguments about an arcane legal issue in an unorthodox manner.It will be the latest example of how her unusual handling of the case has now become business as usual.Over the past several months, Judge Cannon, who was appointed by Mr. Trump in his final days in office, has made a number of decisions that have prompted second-guessing and criticism among legal scholars following the case. Many of her rulings, on a wide array...