Former Rep. Adam Kinzinger (R-IL), whose speech at the Democratic National Convention served as a highlight of the event due to the GOP veteran’s across-the-aisle endorsement of Vice President Kamala Harris, on Saturday highlighted a development from the DNC that he says “will be written about for years.” Kinzinger, who is said to be facing an “uphill battle” as he tries to change Republican minds to support Harris, took to social media over the weekend to talk about what happened. “Something happened at the DNC that will be written about for years,” the ex-lawmaker said. “Donald Trump has giv…