fix(repl-sdk): make {#custom-id} heading suffix actually set the id

packages/repl-sdk/src/compilers/markdown/heading-id.js

@@ -63,8 +63,20 @@ export function headingId(options = { defaults: false }) {
       if (lastChild && lastChild.type === 'text') {
         const string = lastChild.value.replace(/ +$/, '');
         const matched = string.match(/ {#([^]+?)}$/);
+        const suffix = matched?.[0];
+        const customId = matched?.[1];
+
+        if (suffix && customId) {
+          const remaining = string.slice(0, -suffix.length);
+
+          if (remaining) {
+            lastChild.value = remaining;
+          } else {
+            node.children.pop();
+          }
+
+          setNodeId(node, customId);
 
-        if (matched) {
           return;
         }
       }

packages/repl-sdk/src/compilers/markdown/parse.test.ts

@@ -253,6 +253,20 @@ describe('heading ids', () => {
 
     expect(result.text).toContain('id="a-s-b"');
   });
+
+  it('uses a {#custom-id} suffix as the id and strips it from the text', async () => {
+    const result = await parseMarkdown(`## A very long heading {#short-id}`, { ...defaults });
+
+    expect(result.text).toBe('<h2 id="short-id">A very long heading</h2>');
+  });
+
+  it('supports {#custom-id} on a heading ending in formatting', async () => {
+    const result = await parseMarkdown(`## Use \`parseMarkdown\` here {#parse}`, {
+      ...defaults,
+    });
+
+    expect(result.text).toBe('<h2 id="parse">Use <code>parseMarkdown</code> here</h2>');
+  });
 });
 
 describe('options', () => {