Fix infinite loop and broken list rendering

[treo]

In our use of SvelteMarkdown I ran into a couple of weird issues:

1. Some lists would render wrong, by repeating their contents. e.g.
   

2. Others would crash with a message like: Uncaught (in promise) RangeError: Maximum call stack size exceeded when given a simple nested list.
   

I've tracked both issues down to the Parser component where the recursive call would receive ...rest instead of a more limited set of parameters like ...parserRest like it is done in other places in the component.

I've adapted both of the list related calls to only pass on the more limited set of parameters and extended the tests to cover both types of nested lists and a mixed usage case.