horse: add 564 ability type

While we're here adding the formatting, also adjust DD's wording and fix
the units on lane change speed skills.

Fixes #25.

skill.go

@@ -81,25 +81,28 @@ func (a Ability) String() string {
 		case AbilityRushedChance:
 			r = append(r, a.Value.String()...)
 			r = append(r, '%')
-		case AbilityGateDelay:
+		case AbilityGateDelay, AbilityActivateRare:
-			// This skill type in particular should be × instead of +.
+			// These skill types in particular should be × instead of +.
 			r = append(r[:len(r)-1], "×"...)
 			r = append(r, a.Value.String()...)
 		case AbilityFrenzy, AbilityAddGateDelay:
 			r = append(r, a.Value.String()...)
 			r = append(r, 's')
-		case AbilityCurrentSpeed, AbilityCurrentSpeedUp, AbilityTargetSpeed, AbilityLaneSpeed:
+		case AbilityCurrentSpeed, AbilityCurrentSpeedUp, AbilityTargetSpeed:
 			r = append(r, a.Value.String()...)
 			r = append(r, " m/s"...)
+		case AbilityLaneSpeed:
+			r = append(r, a.Value.String()...)
+			r = append(r, " CW/s"...)
 		case AbilityAccel:
 			r = append(r, a.Value.String()...)
 			r = append(r, " m/s²"...)
 		case AbilityLaneChange:
-			// This skill type should be "to 0.5 track widths."
+			// This skill type should be "to 0.5 CW."
 			// (The only skill that has it is Dodging Danger/Sixth Sense.)
 			r = append(r[:len(r)-1], "to "...)
 			r = append(r, a.Value.String()...)
-			r = append(r, " track widths"...)
+			r = append(r, " CW"...)
 		}
 	}
 	switch a.Target {
@@ -168,7 +171,8 @@ const (
 	AbilityLaneSpeed      AbilityType = 28 // Lane change speed
 	AbilityRushedChance   AbilityType = 29 // Rushed chance
 	AbilityAccel          AbilityType = 31 // Acceleration
-	AbilityLaneChange     AbilityType = 35 // Forced lane change
+	AbilityLaneChange     AbilityType = 35 // Set target lane
+	AbilityActivateRare   AbilityType = 37 // Activate rare skills
 )
 
 type AbilityValueUsage int8