From its first line — “Hi, my name is Dory, and I suffer from short-term memory loss” — it’s clear that Pixar’s “Finding Dory” will deliver very pointed messages about disability and how society treats members of the disabled community. The film opens on a flashback. Dory is tiny, her voice making clear that she’s school-aged and just beginning to navigate a world beyond her doting, overprotective parents. And because we know Dory (Ellen Degeneres) so well from “Finding Nemo,” the 2003 film that introduced her character, we understand what’s at stake for her future.