Whenever I change the font size doing so is usually temporary and I usually go back to the default font size in after a short time. Currently I do so by changing to a different profile and discarding the change, which resets the font size to the default. I fell like there should be a shortcut for resetting the size.
I could not find an appropriate icon, so I left it without icon.
The default shortcut ctrl+r seemed reasonable and easy to type, 'r' reset.