Improve Wiki TOC (#24137)

The old code has a lot of technical debts, eg: `repo/wiki/view.tmpl` /
`Iterate`

This PR improves the Wiki TOC display and improves the code.

---------

Co-authored-by: delvh <dev.lh@web.de>

modules/markup/renderer.go

@@ -16,6 +16,16 @@ import (
 
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/yuin/goldmark/ast"
+)
+
+type RenderMetaMode string
+
+const (
+	RenderMetaAsDetails RenderMetaMode = "details" // default
+	RenderMetaAsNone    RenderMetaMode = "none"
+	RenderMetaAsTable   RenderMetaMode = "table"
 )
 
 type ProcessorHelper struct {
@@ -63,7 +73,8 @@ type RenderContext struct {
 	GitRepo          *git.Repository
 	ShaExistCache    map[string]bool
 	cancelFn         func()
-	TableOfContents  []Header
+	SidebarTocNode   ast.Node
+	RenderMetaAs     RenderMetaMode
 	InStandalonePage bool // used by external render. the router "/org/repo/render/..." will output the rendered content in a standalone page
 }