remove outline on step number

Author: orifu

src/style/_prettify.scss

@@ -3,6 +3,7 @@
 @use './components/code';
 @use './components/file-tree';
 @use './components/pagination';
+@use './components/steps';
 
 :root {
     // smaller titles

src/style/components/_steps.scss

@@ -0,0 +1,3 @@
+.sl-steps > li::before {
+    box-shadow: none;
+}