Create Class, Interface and Enums as expanders in the TOC for .NET Documentation

[UmaHarano]

Hi,
The TOC for my .NET assembly namespace types lists "Classes" "Interface" and "Enums" as "Toc Titles". Is there a way to make them into expanders in the TOC instead? This will make the TOC more compact. I have many types in a namespace and it would nice to collapse them.

I want this behavior instead:

[UmaHarano]

I am using the following attributes:

"metadata": [
    {
      "src": [
        {
          "src": "src",
          "files": [
            "xxxxx.csproj"
          ]
        }
      ],
      "dest": "api/xxxx",      
      "memberLayout": "separatePages",
      "outputFormat": "apiPage"
    },

[filzrev]

Currently there is no options available to change TOC categories behaviors.

To change behaviors. It require source code changes.
So it might be better to create `[Feature Request] issue instead.

Background
TOC for ApiPage/Markdown is generated by DotnetApiCatalog.Toc.cs.
And categories labels are inserted by at following lines.

docfx/src/Docfx.Dotnet/DotnetApiCatalog.Toc.cs

Lines 214 to 244 in df66b7d

	static void SortToc(List<TocNode> items, bool root)
	{
	items.Sort((a, b) => a.type.CompareTo(b.type) is var r && r is 0 ? a.name.CompareTo(b.name) : r);
	if (!root)
	{
	InsertCategory(TocNodeType.Class, "Classes");
	InsertCategory(TocNodeType.Struct, "Structs");
	InsertCategory(TocNodeType.Interface, "Interfaces");
	InsertCategory(TocNodeType.Enum, "Enums");
	InsertCategory(TocNodeType.Delegate, "Delegates");
	InsertCategory(TocNodeType.Constructor, "Constructors");
	InsertCategory(TocNodeType.Field, "Fields");
	InsertCategory(TocNodeType.Property, "Properties");
	InsertCategory(TocNodeType.Method, "Methods");
	InsertCategory(TocNodeType.Event, "Events");
	InsertCategory(TocNodeType.Operator, "Operators");
	}
	foreach (var item in items)
	{
	if (item.items is not null)
	SortToc(item.items, root: false);
	}
	void InsertCategory(TocNodeType type, string name)
	{
	if (items.FirstOrDefault(i => i.type == type) is { } node)
	items.Insert(items.IndexOf(node), new() { name = name });
	}
	}

Example code to change behaviors

I've confirmed it can display expandable categories.
By manually restructure TOC items.

Code changes

            void InsertCategory(TocNodeType type, string name)
            {
                if (items.All(i => i.type == type))
                    return;

                if (items.FirstOrDefault(i => i.type == type) is { } node)
                {
                    var head = new TocNode { name = name, items = items.Where(x => x.type == type).ToList() };
                    items.Insert(items.IndexOf(node), head);
                    items.RemoveAll(x => x.type == type);
                }
            }

[UmaHarano]

@filzrev
Thank you! I made a new FeatureRequest here: #9934