Issue #25461: Rephrase os.walk() doc

Patch written by Bernt Røskar Brenna.
diff --git a/Misc/ACKS b/Misc/ACKS
index 32208f5..0c7d7d9 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1179,6 +1179,7 @@
 Paul Rubin
 Sam Ruby
 Demur Rumed
+Bernt Røskar Brenna
 Audun S. Runde
 Eran Rundstein
 Rauli Ruohonen