Allow fa classes

[GiorgioMiglia]

Allow to pass Font Awesome classes to customize the icons like using Fixed width ones:

https://docs.fontawesome.com/web/style/fixed-width

[gadenbuie]

You can use .add_class() on the icon_svg() result to add classes, but we don't include any styles from Font Awesome. icon_svg() just returns the SVG of the icon.

Here's an example (note again that fa-fw and fa-rotate-90 don't "work" because those styles aren't defined):

from shiny.express import ui
from faicons import icon_svg

ui.h2("Font Awesome Classes")

with ui.p():
    icon_svg("house").add_class("fa-fw fa-rotate-90")
    " Home"

with ui.p():
    icon_svg("download").add_class("fa-fw")
    " Download"