Inline enums don't show when a default value is present

This will not show the inline enum.

```apib
        + scale   : `4` (enum[number], optional) - scale from 0 (worst) to 1 (best)
            + 0
            + 1
```

This will only show the inline enum default value as a normal field.

```apib
        + scale   : `4` (enum, optional) - scale from 0 (worst) to 1 (best)
            + 0
            + 1
```