Rename token_symbol to token_bound

Change-Id: I3e4f35c1fc65b542e948659d94437e818fc1f136
diff --git a/src/all/allpref.xfst b/src/all/allpref.xfst
index 7175d0b..6d8f3bb 100644
--- a/src/all/allpref.xfst
+++ b/src/all/allpref.xfst
@@ -8,7 +8,7 @@
 !  - https://github.com/coltekin/TRmorph/tokenize.xfst by Çağrı Çöltekin (2011-2015)
 !    under the MIT License
 
-define NLout "@_TOKEN_SYMBOL_@";
+define NLout "@_TOKEN_BOUND_@";
 ! define NLout "\u000a";
 
 define Digit [%0|1|2|3|4|5|6|7|8|9];