Function signatures containing structs appear as `undefined`

I noticed that structs do not render in the docs with a description. This can be seen in the docs for `set()` in `Bar.sol` found in this repo.

```md
### set

```solidity
function set(IBar.T t) external nonpayable
```





#### Parameters

| Name | Type | Description |
|---|---|---|
| t | IBar.T | undefined |
```
