Adds a verb_exclaim var. Fixes #8478.

Also makes saymods transmitted through the radio system for upcoming NTSL integration.

code/modules/library/lib_machines.dm

@@ -164,7 +164,7 @@ var/global/list/datum/cachedbook/cachedbooks // List of our cached book datums
 	screenstate = 0 // 0 - Main Menu, 1 - Inventory, 2 - Checked Out, 3 - Check Out a Book
 	verb_say = "beeps"
 	verb_ask = "beeps"
-	verb_yell = "beeps"
+	verb_exclaim = "beeps"
 	var/buffer_book
 	var/buffer_mob
 	var/upload_category = "Fiction"