By Diane Bartz WASHINGTON (Reuters) -The U.S. Federal Trade Commission, which enforces antitrust law, proposed a rule that would ban companies from requiring workers to sign noncompete provisions as well as some training repayment agreements, which companies use to keep workers from leaving for better jobs, the agency said on Thursday. Noncompete agreements “block workers from freely switching jobs, depriving them of higher wages and better working conditions, and depriving businesses of a talent pool that they need to build and expand,” said FTC Chair Lina Khan in a statement. The proposed ru…