Links to namespaces not generated - this worked in prior versions

**Operating System**: `Windows`

**DocFX Version Used**: 2.56.4

**Template used**: `default`

**Steps to Reproduce**:

1. Include index.md in api folder
2. Include reference to index.md in the root toc.yml
3. Include references in index.md to namespaces in code (e.g. - ``)

**Expected Behavior**: The `` would be replaced with a link to the page generated for the `MyNamespace` namespace. This worked in earlier versions of docFx. We are *sure* it worked in 2.43.1, but we are not sure which release broke the behavior.

**Actual Behavior**: A link is *not* generated. Instead, the `` is added to the resulting index.html page.