You can no longer pull something you're buckled to. (#18957)

* No longer possible to pull something you're riding

* hal9000PR is redundant

* remove brackets

Co-authored-by: adrermail@gmail.com <adrermail@gmail.com>

code/game/objects/buckling.dm

@@ -55,6 +55,7 @@
 	if((!can_buckle && !force) || M.buckled || (length(buckled_mobs) >= max_buckled_mobs) || (buckle_requires_restraints && !M.restrained()) || M == src)
 		return FALSE
 	M.buckling = src
+
 	if(!M.can_buckle() && !force)
 		if(M == usr)
 			to_chat(M, "<span class='warning'>You are unable to buckle yourself to [src]!</span>")
@@ -77,6 +78,10 @@
 		M.set_body_position(STANDING_UP)
 	else
 		M.set_body_position(LYING_DOWN)
+	
+	if(M.pulling && M.pulling == src)
+		M.stop_pulling()
+
 	M.buckling = null
 	M.buckled = src
 	M.setDir(dir)