Add FULL option to XINFO SUMMARY

[agusdmb]

Pull Request check-list

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• Does $ tox pass with this change (including linting)?
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• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

Description of change

Add flag FULL to XINFO STREAM supported from Redis 6.0.0

https://redis.io/commands/xinfo

[chayim]

@agusdmb Thanks for the contribution! I appreciate your adding in the groups/entries support as part of this, as opposed to just flushing the FULL option through, as per the docs. Much appreciated!