Fix link styles in Safari (again)

[lb-]

• fixes Safari: Links invisible on dark mode docs, barely visible in light mode #206
• fixes Link style broken on Safari #155 again
• Not sure why we keep running into these issues but hopefully fixed for good now - basically just bypassing the shorthand variant completely as it does not work as expected

https://caniuse.com/mdn-css_properties_text-decoration_shorthand - requires prefix if we want to use it but simpler to keep this out of the scss.

Screenshots - Before

Left is Firefox, Right is Safari

Screenshots - After

Left is Firefox, Right is Safari

[lb-]

Thanks @tbrlpld