add missing default

Author: cscheid

src/resources/formats/revealjs/quarto.scss

@@ -22,6 +22,7 @@ $font-family-monospace-block: $font-family-monospace !default;
 $font-family-monospace-inline: $font-family-monospace !default;
 $link-weight: $font-weight-base !default;
 $link-color-bg: transparent !default;
+$link-decoration: inherit !default;
 
 // main colors
 $body-bg: #fff !default;