doc example on to_formatted_text

The example on https://python-prompt-toolkit.readthedocs.io/en/2.0.5/pages/printing_text.html

from prompt_toolkit.formatted_text import to_formatted_text, HTML
from prompt_toolkit import print_formatted_text

html = HTML('<aaa>Hello</aaa> <bbb>world</bbb>!')
text = to_formatted_text(html, style='class:my_html bg:#00ff00 italic')

print_formatted_text(text)

produces just the output

[('class:my_html bg:#00ff00 italic class:aaa', 'Hello'), ('class:my_html bg:#00ff00 italic ', ' '), ('class:my_html bg:#00ff00 italic class:bbb', 'world'), ('class:my_html bg:#00ff00 italic ', '!')].

I assume this is not what was intended? So it is less clear what it is intended to show and how. It also does not accept a prompt_toolkit.styles.Style object as style, as one would have expected or hoped.

Start with the to_formatted_text example in pages/printing_text.html and reproduce the shown output using the documented prompt_toolkit imports. Determine whether the example or the documented Style-object behavior is incorrect; done means the example clearly demonstrates its intended result and accurately describes accepted style inputs.