Improve readability within Message.parse

Co-authored-by: James Hilton-Balfe <[email protected]>

src/betterproto/__init__.py

@@ -1327,9 +1327,7 @@ def parse(self: T, data: bytes) -> T:
             The initialized message.
         """
         with BytesIO(data) as stream:
-            self.load(stream)
-
-        return self
+            return self.load(stream)
 
     # For compatibility with other libraries.
     @classmethod