Chief Executive Jack Dorsey’s job is safe following a review of his leadership requested by one of Wall Street’s toughest activist investors, the social-networking company said in an SEC filing Monday. The news, and Twitter’s avowal to start the stock-repurchase plan it announced just before the pandemic, sent Twitter shares up 2% in after-hours trading. Monday’s filing comes eight months after Twitter reached an agreement with Elliott Management to buy back $2 billion of its shares, partially funded through a $1 billion investment from private equity firm Silver Lake. Twitter shares are up 23% this year. The broader S&P 500 index has improved 2.5% this year.