fixed memory leak in core/prof/spall/doc.odin example code

core/prof/spall/doc.odin

@@ -18,6 +18,8 @@ Example:
 		defer spall.context_destroy(&spall_ctx)
 
 		buffer_backing := make([]u8, spall.BUFFER_DEFAULT_SIZE)
+		defer delete(buffer_backing)
+
 		spall_buffer = spall.buffer_create(buffer_backing, u32(sync.current_thread_id()))
 		defer spall.buffer_destroy(&spall_ctx, &spall_buffer)