Use less margin in revealjs than in bootstrap

As space is more limited in revealjs

This match current behavior in quarto 1.5 too

Author: cderv

src/resources/formats/revealjs/quarto.scss

@@ -99,8 +99,8 @@ $input-panel-bg: rgba(248, 249, 250, 1) !default;
 $callout-border-width: 0.3rem !default;
 $callout-border-scale: 0% !default;
 $callout-icon-scale: 10% !default;
-$callout-margin-top: 1.25rem !default;
-$callout-margin-bottom: 1.25rem !default;
+$callout-margin-top: 1rem !default;
+$callout-margin-bottom: 1rem !default;
 $callout-color-note: #0d6efd !default;
 $callout-color-tip: #198754 !default;
 $callout-color-important: #dc3545 !default;