Add countdown fact documentation

adapters/BasicAdapter/src/main/kotlin/me/gabber235/typewriter/entries/fact/CooldownFact.kt → adapters/BasicAdapter/src/main/kotlin/me/gabber235/typewriter/entries/fact/CountdownFact.kt

@@ -14,18 +14,31 @@ import java.time.LocalDateTime
 import kotlin.math.max
 
 @Entry(
-    "cooldown_fact",
-    "Cooldown fact for tracking time also when player is offline",
+    "countdown_fact",
+    "A fact that counts down from the set value",
     Colors.BLUE,
     "material-symbols:person-pin"
 )
-class CooldownFact(
+/**
+ * The `Cooldown Fact` is a fact reflects the time since the last set value.
+ *
+ * When the value is set, it will count every second down from the set value.
+ *
+ * Suppose the value is set to 10.
+ * Then after 3 seconds, the value will be 7.
+ *
+ * The countdown will continue regardless if the player is online/offline or if the server is online/offline.
+ *
+ * ## How could this be used?
+ * This can be used to create a cooldown on a specific action.
+ * For example, daily rewards that the player can only get once a day.
+ */
+class CountdownFact(
     override val id: String = "",
     override val name: String = "",
     override val comment: String = "",
     override val group: Ref<GroupEntry> = emptyRef(),
 ) : PersistableFactEntry, ExpirableFactEntry {
-
     override fun read(id: FactId): FactData {
         val data = super<PersistableFactEntry>.read(id)
         return FactData(calculateValue(data), data.lastUpdate)