Change Norwegian Nynorsk translation of ‘spell’ in episodes 24 and 33

Changes the translation of ‘spell’ from ‘(trylle)formular’ to ‘(trylle)formel’. Both translations are correct, but ‘formel’ is shorter and has a simpler noun inflection. And it’s the term used in the Norwegian translation of the Harry Potter books. :) A few speech bubbles needed size or line-breaking adjustments.