v3.1.1

Improves accessibility friendliness of HTML with the addition of preAttributes and codeAttributes to options for global attribute additions to the rendered HTML. Pass in an object literal! Thank you @ChrisBrownie55 for #48.

Read more at: https://accessibilityinsights.io/info-examples/web/scrollable-region-focusable/

Milestone: https://github.com/11ty/eleventy-plugin-syntaxhighlight/milestone/9?closed=1