Data Catalog: Update docstrings (via synth).

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Here's the log from Synthtool:

synthtool > Executing /tmpfs/src/git/autosynth/working_repo/datacatalog/synth.py.
synthtool > Ensuring dependencies.
synthtool > Pulling artman image.
latest: Pulling from googleapis/artman
Digest: sha256:6018498e15310260dc9b03c9d576608908ed9fbabe42e1494ff3d827fea27b19
Status: Image is up to date for googleapis/artman:latest
synthtool > Cloning googleapis.
synthtool > Running generator for google/cloud/datacatalog/artman_datacatalog_v1beta1.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1.
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/datacatalog/v1beta1/timestamps.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto/timestamps.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/datacatalog/v1beta1/schema.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto/schema.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/datacatalog/v1beta1/tags.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto/tags.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/datacatalog/v1beta1/table_spec.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto/table_spec.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/datacatalog/v1beta1/search.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto/search.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/datacatalog/v1beta1/datacatalog.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto/datacatalog.proto
synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/datacatalog-v1beta1/google/cloud/datacatalog_v1beta1/proto.
synthtool > Replaced '__doc__ = """Attributes:' in google/cloud/datacatalog_v1beta1/proto/tags_pb2.py.
synthtool > Replaced '__doc__ = """Attributes:' in google/cloud/datacatalog_v1beta1/proto/datacatalog_pb2.py.
.coveragerc
.flake8
MANIFEST.in
noxfile.py.j2
setup.cfg
Running session blacken
Creating virtualenv using python3.6 in .nox/blacken
pip install black
black docs google tests noxfile.py setup.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/gapic/enums.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/gapic/data_catalog_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/gapic/transports/data_catalog_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/schema_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/schema_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/datacatalog_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/search_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/search_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/table_spec_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/table_spec_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/tags_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/timestamps_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/timestamps_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/noxfile.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/gapic/data_catalog_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/tags_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/tests/unit/gapic/v1beta1/test_data_catalog_client_v1beta1.py
reformatted /tmpfs/src/git/autosynth/working_repo/datacatalog/google/cloud/datacatalog_v1beta1/proto/datacatalog_pb2.py
All done! ✨ 🍰 ✨
22 files reformatted, 6 files left unchanged.
Session blacken was successful.
synthtool > Cleaned up 2 temporary directories.
synthtool > Wrote metadata to synth.metadata.