Fix magic number

Author: aisk

Include/internal/pycore_magic_number.h

@@ -294,7 +294,7 @@ Known values:
     Python 3.15a4 3661 (Lazy imports IMPORT_NAME opcode changes)
     Python 3.15a8 3662 (Add counter to RESUME)
     Python 3.15a8 3663 (Merge GET_ITER and GET_YIELD_FROM_ITER. Modify SEND to make it a bit more like FOR_ITER)
-    Python 3.15a8 3663 (Remove DELETE_ATTR opcode)
+    Python 3.15a8 3664 (Remove DELETE_ATTR opcode)
 
 
     Python 3.16 will start with 3700