fix formatting for tags within fences (#210)

src/formatter.test.ts

@@ -488,4 +488,26 @@ Yes!
     check(source, expected);
     stable(expected);
   });
+
+  it('fences with block level tags', () => {
+    const source = `{% tab %}
+\`\`\`json {% filename="package.json" %}
+{
+  "dependencies": {
+    ...
+    {% highlight type="remove" %}
+    "beta": "1.2.3",
+    {% /highlight %}
+    {% highlight type="add" %}
+    "main": "1.2.4",
+    {% /highlight %}
+    ...
+  }
+}
+\`\`\`
+{% /tab %}
+`;
+
+    check(source, source);
+  });
 });

src/formatter.ts

@@ -185,7 +185,8 @@ function* formatNode(n: Node, o: Options = {}) {
       yield* formatAnnotations(n);
       yield NL;
       yield indent;
-      yield* formatChildren(n, no);
+      // TODO use formatChildren once we can differentiate inline from block tags within fences
+      yield n.attributes.content; // yield* formatChildren(n, no);
       yield indent;
       yield '```';
       yield NL;