Add new search term for datadog config

[NobodysNightmare]

What does this PR do?

We found out that the search was not simplified as much as we hoped for by the given keywords, because newer versions of ddtrace-rb (at least 1.5) do log under the key "DATADOG CONFIGURATION". Thus we didn't find the startup logs when we were looking for them.

Motivation

What inspired you to submit this pull request?

Incorrect documentation.

Additional Notes

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Reviewer checklist

• [ ] Review the changed files.
• [ ] Review the URLs listed in the Preview section.
• [ ] Check images for PII
• [ ] Review any mentions of "Contact Datadog support" for internal support documentation.

[NobodysNightmare]

Cross reference to ddtrace-rb: https://github.com/DataDog/dd-trace-rb/blob/da797293caaa1bbde3d2993709dabb956e457e84/lib/datadog/core/diagnostics/environment_logger.rb#L34

[kayayarai]

@NobodysNightmare Thanks, Jan. Adding this