Refactor markdown render (#30139)

Only split the file into small ones (and rename AttentionTypes to
attentionTypes)

modules/markup/markdown/transform_link.go

@@ -0,0 +1,31 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import (
+	"code.gitea.io/gitea/modules/markup"
+	giteautil "code.gitea.io/gitea/modules/util"
+
+	"github.com/yuin/goldmark/ast"
+	"github.com/yuin/goldmark/text"
+)
+
+func (g *ASTTransformer) transformLink(ctx *markup.RenderContext, v *ast.Link, reader text.Reader) {
+	// Links need their href to munged to be a real value
+	link := v.Destination
+	isAnchorFragment := len(link) > 0 && link[0] == '#'
+	if !isAnchorFragment && !markup.IsFullURLBytes(link) {
+		base := ctx.Links.Base
+		if ctx.IsWiki {
+			base = ctx.Links.WikiLink()
+		} else if ctx.Links.HasBranchInfo() {
+			base = ctx.Links.SrcLink()
+		}
+		link = []byte(giteautil.URLJoin(base, string(link)))
+	}
+	if isAnchorFragment {
+		link = []byte("#user-content-" + string(link)[1:])
+	}
+	v.Destination = link
+}