[Ada] Adjust reference in comment

[Pierre-Marie de Rodat via Gcc-patches]

This is needed after the creation of Returns_On_Secondary_Stack from the
original Requires_Transient_Scope.
Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * sem_util.adb (Indirect_Temp_Needed): Adjust reference in comment.
diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -32129,7 +32129,7 @@ package body Sem_Util is
             --
             --  See Large_Max_Size_Mutable function elsewhere in this
             --  file (currently declared inside of
-            --  Requires_Transient_Scope, so it would have to be
+            --  Returns_On_Secondary_Stack, so it would have to be
             --  moved if we want it to be callable from here).
 
          end Indirect_Temp_Needed;