Standardize quote format in int.from_bytes/to_bytes docstring

The motivation for this is that the unpaired backtick confuses Sphinx,
and inheriting from int (e.g. through enum.IntEnum) is pretty common.
See https://stackoverflow.com/q/77914856 for an example of the problem
this causes.

Objects/longobject.c

@@ -6026,7 +6026,7 @@ int.to_bytes
         the most significant byte is at the beginning of the byte array.  If
         byteorder is 'little', the most significant byte is at the end of the
         byte array.  To request the native byte order of the host system, use
-        `sys.byteorder' as the byte order value.  Default is to use 'big'.
+        'sys.byteorder' as the byte order value.  Default is to use 'big'.
     *
     signed as is_signed: bool = False
         Determines whether two's complement is used to represent the integer.
@@ -6090,7 +6090,7 @@ int.from_bytes
         the most significant byte is at the beginning of the byte array.  If
         byteorder is 'little', the most significant byte is at the end of the
         byte array.  To request the native byte order of the host system, use
-        `sys.byteorder' as the byte order value.  Default is to use 'big'.
+        'sys.byteorder' as the byte order value.  Default is to use 'big'.
     *
     signed as is_signed: bool = False
         Indicates whether two's complement is used to represent the integer.