Improve BTComment

Warn user about having comment as root task or having other tasks as children

bt/tasks/bt_comment.cpp

@@ -11,9 +11,22 @@
 
 #include "bt_comment.h"
 
+#include "bt_task.h"
+
 Ref<BTTask> BTComment::clone() const {
 	if (Engine::get_singleton()->is_editor_hint()) {
 		return BTTask::clone();
 	}
 	return nullptr;
 }
+
+PackedStringArray BTComment::get_configuration_warnings() const {
+	PackedStringArray warnings = BTTask::get_configuration_warnings();
+	if (get_child_count_excluding_comments() > 0) {
+		warnings.append("Can only have other comment tasks as children.");
+	}
+	if (get_parent() == nullptr) {
+		warnings.append("Can't be the root task.");
+	}
+	return warnings;
+}

bt/tasks/bt_comment.h

@@ -21,6 +21,7 @@ class BTComment : public BTTask {
 private:
 public:
 	virtual Ref<BTTask> clone() const override;
+	virtual PackedStringArray get_configuration_warnings() const override;
 };
 
 #endif // BT_COMMENT