Hugo issue with multiple footnotes referencing the same number

[scottmakestech]

If two footnotes reference the same number (e.g. [^3]), this causes an error because Hugo will generate multiple elements with the same ID, which will cause the build to fail since identical IDs is not valid HTML.

This appears fixed in the latest version of Hugo so I'm marking this bug here until we can safely update. https://discourse.gohugo.io/t/multiple-references-to-footnotes/38068/6