src/HOL/Tools/Sledgehammer/sledgehammer_prover.ML

     val thy = Proof_Context.theory_of ctxt
     val (remote_provers, local_provers) =
       sort_strings (supported_atps thy) @ sort_strings (SMT_Config.available_solvers_of ctxt)
       |> List.partition (String.isPrefix remote_prefix)
   in
-    writeln ("Supported provers: " ^ commas (local_provers @ remote_provers) ^ ".")
+    writeln ("Supported provers: " ^ commas (local_provers @ remote_provers))
   end
 
 end;