CITY WEEKLY / JAMAICA PLAIN Though a formal celebration of Anne Sexton's poems and what would've been her 78th year will take place today at the Forest Hills Cemetery, she is often remembered in quieter ways. Atop the granite ledge of her hillside grave, visitors have placed stones, flowers, pens, and notes for the Newton-born Pulitzer Prize- winning poet who committed suicide in 1974. Cecily Miller, the director of the cemetery educational trust, mentioned seeing an "AA coin" on the Sexton stone recently. "We don't always see her fans," said Miller, "but we have evidence they visit throughout...