Expected Behaviour

When creating a popup and providing a title for the options table but no border, a title is drawn above the contents

Actual Behaviour

Title isn't drawn at all

Steps to reproduce

:lua require('popup').create('test', {line=30, col=30, title='test title')
Note: provided line and col offset to show title isn't being drawn outside of tabpage
https://asciinema.org/a/aYruKQuEyFYNqhWXUs8Qo9Q4x