Refactors all (F) links into using a define

🆑
bugfix: Clicking the (F) link when an AI talks in binary chat will
follow its camera eye, the same as when (F) is clicked for its radio
chat.
/🆑

FOLLOW_LINK is a define that creates the clickable (F) link, so it
doesn't have to be typed painstakingly out every time we want to give
that link to an observer.

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

@@ -29,5 +29,6 @@
 			speaker = S.eyeobj
 		else
 			speaker = V.source
-	src << "<a href=?src=\ref[src];follow=\ref[speaker]>(F)</a> [message]"
+	var/link = FOLLOW_LINK(src, speaker)
+	src << "[link] [message]"