Use HTML5 semantic elements in mirrored wiki content for better summaries in search engines

[nelsonjchen]

This helps optimize search engine summaries of the mirrored content.

Here's an example of the current summary:

The "SC1110 – ShellCheck Wiki. See this page on GitHub · Sitemap." UI chrome leaks into the summary.

Here's an example of my service's summary:

I throw everything content into an <article /> and the chrome doesn't leak into the summary. I throw the other UI chrome into <aside />s or <nav />s.