Issue #23352: Document that Py_buffer.suboffsets must be NULL if no suboffsets

are required.

Doc/c-api/buffer.rst

@@ -98,8 +98,11 @@ The new-style Py_buffer struct
       suboffset value that it negative indicates that no de-referencing should
       occur (striding in a contiguous memory block).
 
+      If all suboffsets are negative (i.e. no de-referencing is needed, then
+      this field must be NULL (the default value). 
+
       Here is a function that returns a pointer to the element in an N-D array
-      pointed to by an N-dimesional index when there are both non-NULL strides
+      pointed to by an N-dimensional index when there are both non-NULL strides
       and suboffsets::
 
           void *get_item_pointer(int ndim, void *buf, Py_ssize_t *strides,