Curly quotes are a particular nuisance, especially in incoming posts. This function removes them before the post (or comment) is inserted in the database. If an older post containing curly quotes is edited, it will save with straight quotes upon database insert.
In the default state, `wp_nav_menu()` classes for `li` elements are useful as CSS and JS selectors, but are not human-friendly. I prefer to use selectors like `.menu-item-archives` instead of `.menu-item-38008`. This function creates a human-readable class on the `li` elements generated by `wp_nav_menu()`.