`value_box` and related docs have broken examples

[phobson]

It appears that icons.py has disappeared from the live examples of value_box and its ilk:

https://shiny.posit.co/py/api/core/ui.value_box.html#examples

[phobson]

Oops. Just saw this: #181

Sorry for the noise. Closing as redundant

[gadenbuie]

Thanks again, upstream issue is: posit-dev/py-shiny#1568