Expanded ghost following.

Ghosts can now follow the Eye of a speaking mob, if it has one, or the body of someone who has died.
Partial port of https://github.com/ParadiseSS13/Paradise/pull/1151.

code/modules/mob/dead/observer/observer.dm

@@ -681,3 +681,16 @@ mob/dead/observer/MayRespawn(var/feedback = 0)
 			src << "<span class='warning'>antagHUD restrictions prevent you from respawning.</span>"
 		return 0
 	return 1
+
+/proc/ghost_follow_link(var/atom/target, var/atom/ghost)
+	if((!target) || (!ghost)) return
+	. = "<a href='byond://?src=\ref[ghost];track=\ref[target]'>follow</a>"
+
+	if(istype(target, /mob/dead/observer))
+		var/mob/dead/observer/O = target
+		if(O.mind && O.mind.current)
+			. += "|<a href='byond://?src=\ref[ghost];track=\ref[O.mind.current]'>body</a>"
+	else if(istype(target, /mob)) // Eye follow links
+		var/mob/M = target
+		if(M.client && M.eyeobj) // No point following clientless eyes
+			. += "|<a href='byond://?src=\ref[ghost];track=\ref[M.eyeobj]'>eye</a>"

code/modules/mob/hear_say.dm

@@ -55,7 +55,7 @@
 			return
 		if(speaker_name != speaker.real_name && speaker.real_name)
 			speaker_name = "[speaker.real_name] ([speaker_name])"
-		track = "(<a href='byond://?src=\ref[src];track=\ref[speaker]'>follow</a>) "
+		track = "([ghost_follow_link(speaker, src)]) "
 		if(client.prefs.toggles & CHAT_GHOSTEARS && speaker in view(src))
 			message = "<b>[message]</b>"
 
@@ -180,7 +180,7 @@
 	if(istype(src, /mob/dead/observer))
 		if(speaker_name != speaker.real_name && !isAI(speaker)) //Announce computer and various stuff that broadcasts doesn't use it's real name but AI's can't pretend to be other mobs.
 			speaker_name = "[speaker.real_name] ([speaker_name])"
-		track = "[speaker_name] (<a href='byond://?src=\ref[src];track=\ref[speaker]'>follow</a>)"
+		track = "[speaker_name] ([ghost_follow_link(speaker, src)])"
 
 	var/formatted
 	if(language)

code/modules/mob/mob_helpers.dm

@@ -555,7 +555,7 @@ proc/is_blind(A)
 			var/lname
 			if(subject)
 				if(subject != M)
-					follow = "(<a href='byond://?src=\ref[M];track=\ref[subject]'>follow</a>) "
+					follow = "([ghost_follow_link(subject, M)]) "
 				if(M.stat != DEAD && M.client.holder)
 					follow = "(<a href='?src=\ref[M.client.holder];adminplayerobservejump=\ref[subject]'>JMP</a>) "
 				var/mob/dead/observer/DM