[REQ] [angular-typescript] Add documentation for `RequestParams` with `useSingleRequestParameter = true`

When setting
```yaml
useSingleRequestParameter: true
```

the documentation strings for the properties are missing, e.g.:
```TypeScript
export interface SomeRequestParams {
    id: number;
}
```

I would like to have the documentation strings in the generated interfaces, e.g.:
```TypeScript
export interface SomeRequestParams {
    /**
     * The ID of the entity.
     */
    id: number;
}
```
