SyntaxWarning: invalid escape sequence on google-cloud-cli 509.0.0-0

Using Debian 12, I got these warnings when upgrading to google-cloud-cli **509.0.0-0**:

```
Setting up google-cloud-cli (509.0.0-0) ...
lib/googlecloudsdk/appengine/api/datastore.py:1294: SyntaxWarning: invalid escape sequence '\s'
'^\s*([^\s]+)(\s+(%s)\s*)?$' % '|'.join(OPERATORS),
lib/third_party/antlr3/recognizers.py:516: SyntaxWarning: invalid escape sequence '\<'
"""
lib/third_party/google/cloud/appengine_v1/proto/app_yaml_pb2.py:914: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """\ `Google Cloud Endpoints
lib/third_party/google/cloud/appengine_v1/proto/app_yaml_pb2.py:958: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """URL pattern and description of how the URL should be handled. App
lib/third_party/google/cloud/appengine_v1alpha/proto/app_yaml_pb2.py:958: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """URL pattern and description of how the URL should be handled. App
lib/third_party/google/cloud/appengine_v1/proto/version_pb2.py:1476: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """\ `Cloud Endpoints `__
lib/third_party/google/cloud/appengine_v1beta/proto/app_yaml_pb2.py:958: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """URL pattern and description of how the URL should be handled. App
lib/third_party/google/cloud/appengine_v1alpha/proto/version_pb2.py:1659: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """\ `Cloud Endpoints `__
lib/third_party/google/cloud/appengine_v1beta/proto/version_pb2.py:1556: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """\ `Cloud Endpoints `__
lib/third_party/google/cloud/bigquery_logging_v1/proto/audit_data_pb2.py:2770: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """User-provided metadata for a table.
lib/third_party/google/cloud/bigquery_logging_v1/proto/audit_data_pb2.py:2841: SyntaxWarning: invalid escape sequence '\ '
'__doc__': """User-provided metadata for a dataset.
platform/gsutil/third_party/pyparsing/examples/bigquery_view_parser.py:1712: SyntaxWarning: invalid escape sequence '\s'
"""\

```

Reproduce the Debian 12 upgrade warnings, then inspect the reported locations in lib/googlecloudsdk/appengine/api/datastore.py, lib/third_party/antlr3/recognizers.py, the listed app_yaml_pb2.py and version_pb2.py files, and platform/gsutil/third_party/pyparsing/examples/bigquery_view_parser.py. Determine which warnings are in maintained source versus generated or vendored files; done means the reported installation no longer emits these SyntaxWarnings.

Written by the indexing model from the issue text.