slider to change font size of entry content

[kiberdruzhinnik]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

What feature do you want?

i would like to propose the feature of changing font size entry content.

Why do you want this feature?

current entry content font size may not be suitable for everyone (for instance, for it is too small) so it would be great if one could change it with some kind of slider.