remove some PyBytes_* aliases that are not in 3.x

Include/bytesobject.h

@@ -23,11 +23,5 @@
 #define _PyBytes_FormatLong _PyString_FormatLong
 #define PyBytes_DecodeEscape PyString_DecodeEscape
 #define _PyBytes_Join _PyString_Join
-#define PyBytes_Decode PyString_Decode
-#define PyBytes_Encode PyString_Encode
-#define PyBytes_AsEncodedObject PyString_AsEncodedObject
-#define PyBytes_AsEncodedString PyString_AsEncodedString
-#define PyBytes_AsDecodedObject PyString_AsDecodedObject
-#define PyBytes_AsDecodedString PyString_AsDecodedString
 #define PyBytes_AsStringAndSize PyString_AsStringAndSize
 #define _PyBytes_InsertThousandsGrouping _PyString_InsertThousandsGrouping

Misc/NEWS

@@ -506,6 +506,8 @@ Build
 C-API
 -----
 
+- Some PyBytes_* aliases have been removed because they don't exist in 3.x.
+
 - Issue #5175: PyLong_AsUnsignedLongLong now raises OverflowError
   for negative arguments.  Previously, it raised TypeError.