tune text for document generation

--- a/src/HOL/Enum.thy	Mon Oct 03 14:43:15 2011 +0200
+++ b/src/HOL/Enum.thy	Mon Oct 03 15:39:30 2011 +0200
@@ -766,7 +766,7 @@
 
 subsection {* An executable (reflexive) transitive closure on finite relations *}
 
-text {* Definitions could be moved to Transitive_Closure if they are of more general use. *}
+text {* Definitions could be moved to Transitive Closure theory if they are of more general use. *}
 
 definition ntrancl :: "('a * 'a => bool) => nat => ('a * 'a => bool)"
 where