[Python] Sphinx cannot handle indentation in proto comments

[geigerj]

Observed behavior:

After fixing #401:

Build vision docs:

python execute_pipeline.py \
    --config "../googleapis/gapic/api/artman_vision.yaml,\
    ../googleapis/gapic/lang/doc.yaml" \
    --language python \
    GapicClientPipeline 

cd output

tox -e docs

fails with

/usr/local/google/home/jgeiger/repos/gapi-dev/artman/output/gcloud-python-cloud-vision/.tox/docs/lib/python2.7/site-packages/google/type/latlng_pb2.py:docstring of google.type.latlng_pb2.LatLng:13: ERROR: Unexpected indentation.

Cause

Docstring for LatLng contains indented code blocks.

Solution

For code blocks, we should be able to recognize and format them correctly; this is tracked as #222. However, we still need a solution in the general case of indentation; for example, bigtable protos have indentation that is not a code block.

/cc @bjwatson