fix: generate IDs for HTML headings without id attribute (#36233)

This PR fixes #27383 where HTML headings like `<h1>Title</h1>` in
markdown files would have empty permalink anchors

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/markup/html.go

@@ -314,7 +314,7 @@ func visitNode(ctx *RenderContext, procs []processor, node *html.Node) *html.Nod
 		return node.NextSibling
 	}
 
-	processNodeAttrID(node)
+	processNodeAttrID(ctx, node)
 	processFootnoteNode(ctx, node) // FIXME: the footnote processing should be done in the "footnote.go" renderer directly
 
 	if isEmojiNode(node) {