Update SteamFriends documentation

[superdupergc]

Leaving this mostly so others can see - the steam documentation has been partially updated (see https://partner.steamgames.com/doc/features/enhancedrichpresence#2) to show that you need "steam_display" instead of "status" now, when setting Enhanced Rich Presence status messages, to show text in the friends list.

Additionally, you have to set up a localization file and reference only keys to that localization file, when you set steam_display.