doc: fix styles of the expandable TOC

PR-URL: #56755 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ulises Gascón <[email protected]> Reviewed-By: Claudio Wunder <[email protected]> Reviewed-By: Luigi Pinca <[email protected]>

Author: aduh95

doc/api_assets/style.css

@@ -570,40 +570,28 @@ hr{
 }
 
 .tocul{
-margin:0
+margin:0;
 }
-
-.toclia::before{
-content:"■";
-color:var(--color-text-primary);
-padding-right:1em;
-font-size:0.9em;
+.toc>ul:first-child{
+margin-left:1rem;
+}
+.tocli{
+display: list-item;
+list-style: square;
+}
+.toclia{
+display: inline;
+padding-left:0;
 }
 
 .toclia:hover::before{
 color:var(--white);
 }
 
-.toculula{
+.tocul{
 padding-left:1rem;
 }
 
-.tocululula{
-padding-left:2rem;
-}
-
-.toculululula{
-padding-left:3rem;
-}
-
-.tocululululula{
-padding-left:4rem;
-}
-
-.toculululululula{
-padding-left:5rem;
-}
-
 #toc .stability_0::after,
 .deprecated-inline::after{
 background-color:var(--red2);