include unnamed chained facts in Sledgehammer's relevance filter

--- a/src/HOL/Tools/Sledgehammer/sledgehammer_fact.ML	Wed Dec 06 12:45:51 2023 +0100
+++ b/src/HOL/Tools/Sledgehammer/sledgehammer_fact.ML	Wed Dec 06 12:45:57 2023 +0100
@@ -464,8 +464,7 @@
     val assms = Assumption.all_assms_of ctxt
     val named_locals = Facts.dest_static true [global_facts] local_facts
     val unnamed_locals =
-      Facts.props local_facts
-      |> map #1
+      chained @ map #1 (Facts.props local_facts)
       |> filter (is_useful_unnamed_local_fact ctxt)
       |> map (pair "" o single)