Continue updating event macro comments

data/scripts/std_msgbox.inc

@@ -1,7 +1,7 @@
 Std_MsgboxNPC:
 	lock
 	faceplayer
-	message 0x0
+	message NULL
 	waitmessage
 	waitbuttonpress
 	release
@@ -9,26 +9,26 @@ Std_MsgboxNPC:
 
 Std_MsgboxSign:
 	lockall
-	message 0x0
+	message NULL
 	waitmessage
 	waitbuttonpress
 	releaseall
 	return
 
 Std_MsgboxDefault:
-	message 0x0
+	message NULL
 	waitmessage
 	waitbuttonpress
 	return
 
 Std_MsgboxYesNo:
-	message 0x0
+	message NULL
 	waitmessage
 	yesnobox 20, 8
 	return
 
 Std_MsgboxGetPoints:
-	message 0x0
+	message NULL
 	playfanfare MUS_OBTAIN_B_POINTS
 	waitfanfare
 	waitmessage
@@ -36,7 +36,7 @@ Std_MsgboxGetPoints:
 
 @ Never used, pokenavcall is always used directly instead
 Std_MsgboxPokenav:
-	pokenavcall 0x0
+	pokenavcall NULL
 	waitmessage
 	return