docs: minor comment update for Entity message (#434)

* docs: minor comment update for Entity message PiperOrigin-RevId: 528936266 Source-Link: googleapis/googleapis@4f9e1a0 Source-Link: googleapis/googleapis-gen@14fce92 Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiMTRmY2U5MjUxNWExYWUwNWI4OWNlMmIyOGQ5YmM1N2VjMTJkY2JhNiJ9 * 🦉 Updates from OwlBot post-processor See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md --------- Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]

google/cloud/datastore_v1/types/entity.py

@@ -356,10 +356,7 @@ class Value(proto.Message):
 
 class Entity(proto.Message):
  r"""A Datastore data object.
-
- An entity is limited to 1 megabyte when stored. That *roughly*
- corresponds to a limit of 1 megabyte for the serialized form of this
- message.
+ Must not exceed 1 MiB - 4 bytes.
 
  Attributes:
  key (google.cloud.datastore_v1.types.Key):