WASHINGTON (Reuters) - A U.S. federal judge on Saturday rejected key elements of President Donald Trump’s May executive orders that would make it easier to fire federal employees and reduce their ability to bargain collectively. Judge Ketanji Brown Jackson, of the U.S. District Court for the District of Columbia, said in a court order that Trump’s orders, which also would reduce the amount of time low-performing employees had to improve their performance before being fired, “undermine federal employees’ right to bargain collectively.” Trump signed three executive orders in May that administration officials said would give government agencies greater ability to...