style: add pre and code style

All hljs styles have something like this.

Signed-off-by: Felipe Contreras <[email protected]>

Author: felipec

hljs/felipec.css

@@ -1,3 +1,9 @@
+pre code.hljs {
+  display: block;
+  overflow-x: auto;
+  padding: 1em;
+}
+
 .hljs {
   color: hsl(240, 6.25%, 87.5%);
   background-color: hsl(240, 6.25%, 9.375%);