How to remove extra line space on GitHub markdown bullets/lists?

Question

The GitHub markdown code:

1. First item
* subitem
1. Second item

Generates a big space between the First, Second and the subitem:

How to make the subitem close to the first item, instead of exactly on the middle of them?

This is a Photoshop I did to illustrate the correct output:

Related questions:

user_13271229 · Answer

An admittably "hacky" but still working solution:

1. First item  [< two spaces for the linebreak]
◦ subitem1  [< two spaces for the linebreak]
◦ subitem2
2. Second item