Lists with sub-lists do not export to pdf correctly

[kawilliges]

Prerequisites

• [ X] Reproduced the problem in Safe Mode (may not be approriate if your error involves markdown-preview-plus): http://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
• [X ] Checked that the issue isn't already filed: https://github.com/travs/markdown-pdf/issues)

Issue description

List with sub-lists do not seem to function correctly past 2 levels of indentation / sub-listings. See example below:

Steps to reproduce

Input the following text into a .md document and convert to pdf.

1. Item 1.
  * Point 1.
    * Sub-point of 1.
2. Item 2.
  * Another point.
    * And a final sub-point  

Expected behavior: [What you expect to happen]
Output should look like (and appears so in markdown preview):

1. Item 1.
  * Point 1.
     - Sub-point of 1.
2. Item 2.
  * Another point.
     - And a final sub-point

Actual behavior: [What actually happens]
But output instead looks like:

1. Item 1.
  * Point 1.
  * Sub-point of 1.
2. Item 2.
  * Another point.
  * And a final sub-point

Input

.md contains relatively sensitive material

Versions

Mac OS, version 10.14.6
Atom: 1.45.0
Electron: 4.2.7
Chrome: 69.0.3497.128
Node: v10.11.0

[kawilliges]

Of course, immediately after submitting, I encountered the solution. Github markdown seems to only need 2 spaces / a tab to indent each sub-list; but for markdown-pdf, an additional space (*a total of 3 spaces) are needed to get the sub-lists to correctly display in the pdf. Like so:

1. Item 1.
   --Item 1 (2 spaces preceeding)
   ----- Sub-item 1. (5 spaces preceeding)

and so on.

Not sure if this is by design, or was well-known and i missed it in the documentation / prior issues, but i'll leave it to be closed by the creator.