DUBAI (Reuters) - The Saudi stock market rebounded into positive territory on Sunday after initially dropping sharply in response to a corruption inquiry that led to a string of detentions of prominent political and business figures. The stock index .TASI was up 0.02 percent an hour before the close, after falling 2.2 percent at one stage. Some investors worry the investigation could force people implicated to sell equity holdings. But many think the purge will remove opposition to Crown Prince Mohammed bin Salman, helping him accelerate economic reforms such as privatization and big development projects.    