Rework Navigation Menu Part 2
 * Separate scoping and assignment so that a decision does not need to be made as to whether we should intermix spaces and tabs on the left
 * Restore the previously removed nav-menu class addition to the first unordered list in `#site-navigation`.
 * Restore the `.navigation-main.toggled-on .nav-menu` selector.
 * Remove rules for the `.main-small-navigation ul` selector.