UI option to to edit custom tags' fonts and colors

Before continuing, make sure a similar request does not exists already:
https://github.com/hluk/CopyQ/issues
--> No UI option exists.

**Is your feature request related to a problem? Please describe.**
The custom tag font is too small, and sometimes the color needs to be fine tuned for better readability..

**Describe the solution you'd like**
Along with the option to edit a custom tag, additional UI options to change the font and color of the custom tag(s).
Can, perhaps, be just be added as an extra item in Preferences, Appearance to make it easier.

**Describe alternatives you've considered**
A stylesheet option exists, but a UI option would make it easier.

Referencing a related and closed issue, #3272 and posting this feature request separately as one, for easier tracking, if accepted.

Thanks for considering.