Links aren't inserted when using extensions to show whitespace

Extensions such as [Refined GitHub](https://github.com/sindresorhus/refined-github) and [Render Whitespace on GitHub](https://github.com/glebm/render-whitespace-on-github) replaces whitespace with `<span>` inside of dependency names/paths. Because of this Octolinker doesn't match the text and insert a link for them.

ref: https://github.com/OctoLinker/OctoLinker/pull/836#issuecomment-631359175