Describe the bug
It's current impossible to select an inline format (bold and italic tests) from the start of any list item (empty or not) except the first and then type with that format.

To Reproduce
Steps to reproduce the behavior:

1. Make a list block.
2. Type in the first item
3. Start a second list item
4. Click the "Bold" format or press CTRL + B (also works for Italic button / CTRL + I)
5. Type

Result: Text is unformatted (not bold in this example).

Expected behavior
I should be able to format the beginning of a list item. This is common especially for a pattern like this:

• Topic 1: This is the first topic.
• Topic 2: This is different from the first topic.

Screenshots

Desktop (please complete the following information):
Win 10, Firefox 63 and Chrome 70, WP 5.0-beta3, no plugins, Twenty Nineteen