tleadon

Added a link to accuracy description

2

Closes #11567 Added a link to the page the issue mentioned in a [?](https://lichess.org/page/accuracy) next to accuracy in case the user wonders what accuracy is.

Issue #2083 added a /@ datatag for app launching improvements

1

#2083 Added to solve the issue of links like https://lichess.org/@/valvin1/tv not launching the mobile app.