Ten years ago, David Foster Wallace admitted in “Tense Present,” one of his best and most charming essays, to being a “SNOOT,” which he defined as a “really extreme usage fanatic, the sort of person whose idea of Sunday fun is to look for mistakes in Safire’s column’s prose itself.” He outed himself while writing in Harper’s on Bryan A. Garner’s Dictionary of Modern American Usage, a book, he says, that serves to confirm its author’s “SNOOTitude while undercutting it in tone.”