Implement nested list items

[purrutia]

Is your feature request related to a problem? Please describe.
On a presentation I would like to add a contents slide. In markdown, I usually use nested lists on a markdown file with tabs, for example:

1. Item 1
2. Item 2
3. Sub Item 1
4. Sub Item 2
5. Item 3

But if I do that on slides the result is:

1. Item1
2. Item 2
3. Sub Item 1
4. Sub Item 2
5. Item 3

Describe the solution you'd like
I would like to have nested lists like:

1. Item 1
2. Item 2
3. Sub Item 1
4. Sub Item 2
5. Item 3

Describe alternatives you've considered
Use lookatme instead (works there)

[smangels]

Like that? According to Markdown standard indentation with 4 spaces are required to achieve that. I've tested it in slides version

1. First item
2. Second item
   2.1 First sub item
   2.2 Second sub item
3. Third Item

Which gave =>