Support field names called "state"

Useful for observers

opengeode/sdl92Lexer.py

-# $ANTLR 3.5.2 sdl92.g 2021-04-14 13:02:03
+# $ANTLR 3.5.2 sdl92.g 2021-04-16 11:43:10
 
 import sys
 from antlr3 import *

sdl92.g

@@ -1481,7 +1481,7 @@ priority_signal_id
                 :       ID;
 signal_list_id  :       ID;
 timer_id        :       ID;
-field_name      :       ID;
+field_name      :       ID | STATE;
 signal_route_id :       ID;
 channel_id      :       ID;
 route_id        :       ID;