fix(utils): better handling of code blocks in link replacement (#9046)

packages/docusaurus-utils/src/__tests__/markdownLinks.test.ts

@@ -371,6 +371,32 @@ The following operations are defined for [URI]s:
 [URL](./file.md?foo=bar#baz)
 [URL](./file.md#a)
 [URL](./file.md?c)
+`,
+      }),
+    ).toMatchSnapshot();
+  });
+
+  it('handles unpaired fences', () => {
+    expect(
+      replaceMarkdownLinks({
+        siteDir: '.',
+        filePath: 'docs/file.md',
+        contentPaths: {
+          contentPath: 'docs',
+          contentPathLocalized: 'i18n/docs-localized',
+        },
+        sourceToPermalink: {
+          '@site/docs/file.md': '/docs/file',
+        },
+        fileString: `
+\`\`\`foo
+hello
+
+\`\`\`foo
+hello
+\`\`\`
+
+A [link](./file.md)
 `,
       }),
     ).toMatchSnapshot();