End points where {id} isn't the last element doesn't work with the ids keyword

[AWegnerGitHub]

StackAPI currently makes the, incorrect, assumption that if you are passing something via ids, it is the last element in the end point. This is not the case in many end points.

As an example, you can pass ids to /answers/{ids}/comments.

There are also end points that accept a single id, that would fail as currently implemented. An example of this is /posts/{id}/comments/render

[AWegnerGitHub]

Potential Idea:

User needs to pass something like: answers/{}/comments as the first parameter to fetch and then a list of items to the ids parameter.

If there isn't a parameter passed with a list, an error needs to be thrown.

If the end point is answers, then the list from ids is tacked onto the end (as it does currently)