Support start field of List

[inokawa]

https://github.com/syntax-tree/mdast#list

[timmhayes]

@inokawa I'm hoping to use this package on a project I'm working on, but I'm having an issue with list items. Is it related to this open issue? My markdown looks like this:

Here is a list

1. Item one
2. Item two
3. Item three
4. Item four
5. Item five

Here is another list

1. Item one
2. Item two
3. Item three
4. Item four
5. Item five

It should render with 1-5 and 1-5, but instead the numbering continues with 6-10 as shown: Is this a known problem or are there workarounds I can use to fix this? Thanks!