I’d love this, and for the Author pages too!
For now, I’d recommend going in the .hbs file for the Tags, and adding am extra set of curly brackets to the description tag, so {{description}} becomes {{{description}}}.
Then, once you reopen Publiu, you should be able to use HTML markup in your description field. If you’re not familiar with HTML markup, just use the WYSIWYG post editor to create what you need, and then click on the button that shows the HTML source code. Copy that, and paste it into description.
It’s a workaround, but hopefully it suits you for now.