add djot renderer

_djot.ts

@@ -0,0 +1,44 @@
+import djot from "@djot/djot";
+
+function extractTitle(ast: djot.Doc): string {
+  const firstSection = ast.children.find((c) => c.tag == "section");
+  const firstHeading: djot.Heading | undefined = firstSection?.children.find(
+    (c) => c.tag == "heading",
+  );
+  const headingContent = firstHeading?.children.at(0);
+  const title = headingContent?.tag == "str" ? headingContent.text : undefined;
+  return title ?? "No title";
+}
+
+export function djotRender(content: string): string {
+  return djot.renderHTML(djot.parse(content));
+}
+
+export default async function djotLoader(path: string | URL) {
+  const content = await Deno.readTextFile(path);
+
+  const ast = djot.parse(content);
+
+  djot.applyFilter(ast, () => {
+    return {
+      link: (el) => {
+        if (el.destination) {
+          el.destination = el.destination.replace(
+            /(\.dj)(#[^.\s]+)?$/,
+            (_match: string, _ext: string, section: string) => {
+              return section ? section : "";
+            },
+          );
+        }
+      },
+    };
+  });
+  
+  const title = extractTitle(ast);
+  const html = djot.renderHTML(ast);
+
+  return {
+    title,
+    content: html,
+  };
+}