Update retries documentation

[jonathan343]

This PR updates the Boto3 Retries documentation page to be more accurate in explaining the max_attempts and total_max_attempts config values.

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Historical Context

As documented here, when boto3 added support for the cross-SDK max_attempts config in the AWS config file and the AWS_MAX_ATTEMPTS environment variable, there was a pre-existing max_attempts option in the botocore.Config object that behaved differently. To preserve backwards compatibility, a new total_max_attempts was added to the botocore.Config object to match the behavior of the new AWS config file and env var options.

The current Boto3 Retries documentation is missing this context which may lead to customers confusing the behavior of max_attempts when configuring it in the botocore.Config object.

Testing

I ran the following commands to build the docs to validate the changes render correctly:

# Install Boto3 and dependencies
uv pip install -e .
uv pip install -r requirements-docs.txt

# Build the docs (Note: I modified `boto3/docs/__init__.py` so I only build one service to save time)
cd docs
make clean html

# Host the docs locally and verify updates
cd build/html
python -m http.server

[hssyoo]

Thanks for updating the docs, just had a couple small comments for added clarity. Also did we confirm that max_attempts (in the Config() object) behaves the same between legacy and standard modes? If they differ we should also document that

[hssyoo]

🏆