Add top banner to `docs` to alert user if they have reduced motion enabled

[Etesam913]

• It would say something like, "Alert: Animations won't play for you because you have use-reduced-motion enabled. To disable this, follow the steps here"
• This would help users understand that the library is not broken and that they have to change a setting if they want to see the animations play.
• The alert should be dismissible so it does not stay forever.