make sure that bytearray methods return a new bytearray even if there is no change

Fixes #4348
Reviewed by Brett
diff --git a/Misc/NEWS b/Misc/NEWS
index c8a16b7..c97f6b3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
 Core and Builtins
 -----------------
 
+- Issue #4348: Some bytearray methods returned that didn't cause any change to
+  the bytearray, returned the same bytearray instead of a copy.
+
 - Issue #4317: Fixed a crash in the imageop.rgb2rgb8() function.
 
 - Issue #4230: If ``__getattr__`` is a descriptor, it now functions correctly.