Virtually anyone can edit an entry on Wikipedia, the popular online encyclopedia. But its founder is finding it’s not so easy to cover his tracks after a messy breakup with a TV personality and a dust-up over his expenses began playing out on the Web. It’s not the first time that Jimmy Wales, Wikipedia’s de facto leader, has found his behavior questioned — especially since no subject appears too arcane for dissection by Wikipedia’s passionate community of users. The latest episodes, however, reverberated beyond the usual die-hards.