Make `<code>` elements display as inline blocks

This solves two issues;

- `inline-block` elements will not break apart as was happening prior to b08b53b83b7cf8792e139ddc4ea6f61771f2e9ef
- because `<code>` elements are displayed (at least by Chrome) as `inline`, setting the `overflow` property has no effect; therefore f2eb19b374cd338738c6d913190f0e2aa5e4327e was ineffective for `<code>` blocks (though it did work for `<pre>` blocks)