docs: add some SteamID notes

Author: markus-wa

pkg/demoinfocs/common/player.go

@@ -21,7 +21,7 @@ const (
 type Player struct {
 	demoInfoProvider demoInfoProvider // provider for demo info such as tick-rate or current tick
 
-	SteamID64         uint64             // 64-bit representation of the user's Steam ID
+	SteamID64         uint64             // 64-bit representation of the user's Steam ID. See https://developer.valvesoftware.com/wiki/SteamID
 	LastAlivePosition r3.Vector          // The location where the player was last alive. Should be equal to Position if the player is still alive.
 	UserID            int                // Mostly used in game-events to address this player
 	Name              string             // Steam / in-game user name

pkg/demoinfocs/events/events.go

@@ -410,14 +410,15 @@ type ChatMessage struct {
 // RankUpdate signals the new rank. Not sure if this
 // only occurs if the rank changed.
 type RankUpdate struct {
-	SteamID32  int32
+	SteamID32  int32 // 32-bit variant of the SteamID. See https://developer.valvesoftware.com/wiki/SteamID
 	RankChange float32
 	RankOld    int
 	RankNew    int
 	WinCount   int
 }
 
-// SteamID64 converts SteamID32 from the 32-bit SteamID to a 64-bit variant
+// SteamID64 converts SteamID32 to the 64-bit SteamID variant and returns the result.
+// See https://developer.valvesoftware.com/wiki/SteamID
 func (ru RankUpdate) SteamID64() uint64 {
 	return common.ConvertSteamID32To64(uint32(ru.SteamID32))
 }