Fix completion of multiple arguments in Bukkit commands

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/command/BukkitCommandWrapper.java

@@ -47,6 +47,11 @@ public class BukkitCommandWrapper implements com.mojang.brigadier.Command<Comman
     @Override
     public CompletableFuture<Suggestions> getSuggestions(CommandContext<CommandListenerWrapper> context, SuggestionsBuilder builder) throws CommandSyntaxException {
         List<String> results = server.tabComplete(context.getSource().getBukkitSender(), builder.getInput(), context.getSource().getWorld(), context.getSource().getPosition(), true);
+
+        // These are normally only set based on sub nodes, but we have just one giant args node
+        builder.start = builder.getInput().lastIndexOf(' ') + 1;
+        builder.remaining = builder.getInput().substring(builder.start);
+
         for (String s : results) {
             builder.suggest(s);
         }