Edits to the README

Some minor edits to the `README`:

1. Diacriticals for the word “naïve” because I’m a snob like that.
2. Correct a couple of sample code blocks that were colliding on the symbol `sum`; these could also be corrected by changing the variable/constant name to `total` or similar, but I figured it would be clearer to disambiguate `sum` (noun vs. verb), and would hew closer to the presumed intent, by using the module name.