Fix accuracy of comma-grouped selectors

Use the jQuery `context` argument to limit the scope of the selector.

The rule was previously checked by prepending `.table-wrapper`. When you have a comma-grouped selector `A, B`, this will result in:

```css
.table-wrapper A, B
```

It selects any `B`, even ones outside of `.table-wrapper`. **This bug shows up in the :last-of-type level**, if you use the following selector:

```css
orange:last-of-type, apple:last-of-type
```

Even though this (rather unoptimized) selector should work, it registered as a fail, because an innocent apple in the logo was also selected. To that apple's credit, it joined the party and *shook like there's no tomorrow*.