Fails on @import inside stylesheets

[bep]

I came upon an issue where CSS reload failed because of my SCSS and then my CSS had a font @import.

Uncaught TypeError: link.getAttribute is not a function
    at Reloader.linkHref (livereload.js?port=1313&mindelay=10&v=2:1744)
    at livereload.js?port=1313&mindelay=10&v=2:1642
    at pickBestMatch (livereload.js?port=1313&mindelay=10&v=2:1421)
    at Reloader.reloadStylesheet (livereload.js?port=1313&mindelay=10&v=2:1642)
    at Reloader.reload (livereload.js?port=1313&mindelay=10&v=2:1499)
    at LiveReload.performReload (livereload.js?port=1313&mindelay=10&v=2:1089)
    at Object.message (livereload.js?port=1313&mindelay=10&v=2:1069)
    at Object.message (livereload.js?port=1313&mindelay=10&v=2:708)
    at Parser.process (livereload.js?port=1313&mindelay=10&v=2:1321)
    at Connector._onmessage (livereload.js?port=1313&mindelay=10&v=2:840)

I have debugged this, and it tries to resolve getAttribute in CSSImportRule, which obviously fails. In this case, CSSImportRule has no href and I don't see any way you can handle it without doing it from the owning stylesheet.

I have a patch for this which I will create a PR for in a minute.

See gohugoio/hugo#6106