Undo does not work with markdown buttons

[TheFern2]

Describe the bug
Keyboard undo shortcut does not work if you click on a markdown button from the toolbar. CMD/CTRL + Z

To Reproduce
Steps to reproduce the behavior:

1. Click on H1 or whatever
2. CMD/CTRL + Z
3. Markdown still there

Expected behavior
If hitting a symbol from the toolbar by accident or the wrong one, one should be able to undo from keyboard.

Desktop (please complete the following information):

• Mac Mojave
• Chrome
• Version 75.0.3770.100 (Official Build) (64-bit)

[liyasthomas]

@kodaman2 Issue has been identified. Fixes are on the way.