fix: do not show top-level modules twice in navbar

DocGen4/Output/Navbar.lean

@@ -32,13 +32,12 @@ partial def moduleListDir (h : Hierarchy) : HtmlM Html := do
     [fileNodes]
   </details>
 
-def moduleList : HtmlM (Array Html) := do
+def moduleList : HtmlM Html := do
   let hierarchy := (←getResult).hierarchy
   let mut list := Array.empty
   for (n, cs) in hierarchy.getChildren do
-    list := list.push <h4>{n.toString}</h4>
     list := list.push $ ←moduleListDir cs
-  list
+  return <div "class"="module_list">[list]</div>
 
 def navbar : HtmlM Html := do
   <nav «class»="nav">
@@ -54,7 +53,7 @@ def navbar : HtmlM Html := do
     <div «class»="nav_link"><a href={s!"{←getRoot}references.html"}>references</a></div>
     -/
     <h3>Library</h3>
-    [←moduleList]
+    {← moduleList}
   </nav>
 
 end Output

static/style.css

@@ -268,6 +268,11 @@ nav {
     margin-bottom: 1ex;
 }
 
+/* top-level modules in left navbar */
+.nav .module_list > details {
+    margin-top: 1ex;
+}
+
 .nav details > * {
     padding-left: 2ex;
 }
@@ -287,10 +292,6 @@ nav {
     margin-block-end: 4px;
 }
 
-.nav h4 {
-    margin-bottom: 1ex;
-}
-
 /* People use way too long declaration names. */
 .internal_nav, .decl_name {
     overflow-wrap: break-word;