adding hscroll to wide commit messages

[dlangille]

Sometimes a commit message is long:

Let's not have that page scrollable off to the right. Let's add this to the CSS:

pre.description {
    overflow-x: scroll;
    max-width: 600px;
}

Which gives us this:

However, it is not clear to the viewer that the content is scrollable, as shown here:

What CSS will make that horizontal scrollbar visible when there is overflow?