AI Display Fix + AI.dm Improvements (#21132)

Fixes https://github.com/Aurorastation/Aurora.3/issues/20503

Adds documentation to AI.dm and refactors procs that handle AI
Announcements and AI Emergency Messages

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Co-authored-by: Ben10083 <Ben10083@users.noreply.github.com>

code/controllers/subsystems/initialization/misc_late.dm

@@ -42,4 +42,9 @@ SUBSYSTEM_DEF(misc_late)
 		var/obj/outfit/new_outfit = new outfit_type()
 		GLOB.outfit_cache[new_outfit.name] = new_outfit
 
+	// Load AI Icons here
+	for(var/ai_icon in subtypesof(/datum/ai_icon))
+		var/datum/ai_icon/new_icon = new ai_icon()
+		GLOB.ai_icons[new_icon.name] = ai_icon
+
 	return SS_INIT_SUCCESS