cann: fix typo of CANN.md

Author: shibizhao

docs/backend/CANN.md

@@ -269,4 +269,4 @@ Authors from Peking University: Bizhao Shi ([email protected]), Yuxin Yang (yxyang
 Thanks Tuo Dai and Shanni Li from Huawei Technologies Co., Ltd.
 
 ## TODO
-- Support more models and d
+- Support more models and data types.