Add ping command

purpur-server/minecraft-patches/sources/net/minecraft/commands/Commands.java.patch

@@ -8,6 +8,14 @@
  import org.slf4j.Logger;
  
  public class Commands {
+@@ -245,6 +_,7 @@
+             StopCommand.register(this.dispatcher);
+             TransferCommand.register(this.dispatcher);
+             WhitelistCommand.register(this.dispatcher);
++            org.purpurmc.purpur.command.PingCommand.register(this.dispatcher); // Purpur - Add ping command
+         }
+ 
+         if (selection.includeIntegrated) {
 @@ -488,6 +_,7 @@
      private void runSync(ServerPlayer player, java.util.Collection<String> bukkit, RootCommandNode<SharedSuggestionProvider> rootCommandNode) {
          // Paper end - Perf: Async command map building