Merge branch 'styleUpdate-hr' into 'master'

Updated default styling of horizontal rule <hr>

See merge request gitlab-org/gitlab!50935

app/assets/stylesheets/framework/common.scss

@@ -110,7 +110,7 @@ pre {
 }
 
 hr {
-  margin: 24px 0;
+  margin: 1.5rem 0;
   border-top: 1px solid $gray-darker;
 }