Refactor:book parser use with to handle bytesIO (#11800)

### What problem does this PR solve?

book parser use with to handle bytesIO

### Type of change

- [x] Refactoring

rag/app/book.py

@@ -143,6 +143,7 @@ def chunk(filename, binary=None, from_page=0, to_page=100000,
 
     elif re.search(r"\.doc$", filename, re.IGNORECASE):
         callback(0.1, "Start to parse.")
+        with BytesIO(binary) as binary:
             binary = BytesIO(binary)
             doc_parsed = parser.from_buffer(binary)
             sections = doc_parsed['content'].split('\n')