Change some more signatures :(

onPlayerCommandPreprocess(PlayerChatEvent event) -> onPlayerCommandPreprocess(PlayerCommandPreprocessEvent event)
onBlockFlow(BlockFromToEvent event)     -> onBlockFromTo(BlockFromToEvent event)
onPlayerJoin(PlayerEvent event)         -> onPlayerJoin(PlayerJoinEvent event)
onPlayerQuit(PlayerEvent event)         -> onPlayerQuit(PlayerQuitEvent event)
onPlayerTeleport(PlayerMoveEvent event) -> onPlayerTeleport(PlayerTeleportEvent event)

src/main/java/org/bukkit/event/player/PlayerCommandPreprocessEvent.java

@@ -0,0 +1,9 @@
+package org.bukkit.event.player;
+
+import org.bukkit.entity.Player;
+
+public class PlayerCommandPreprocessEvent extends PlayerChatEvent {
+    public PlayerCommandPreprocessEvent(Player player, String message) {
+        super(player, message);
+    }
+}