Adjust the ad in light of GitHub's new rendering

[jennybc]

Do I want to adjust the formatting of the ad in light of GitHub's new rendering? By which I mean the square brackets around "reprex package" here:

I thought perhaps it was unintentional but @gaborcsardi points out the css, which suggests it's intentional and here to stay.

.markdown-body sup>a::before {
    content: "[";
}

Maybe get rid of "the" and "package"? Get rid of the parentheses around the version number?