Add RBS for Datadog::Tracing.correlation

[p-datadog]

Copy of #4499 but in a branch in this repo to run all of the workflows.

What does this PR do?

Added RBS for Datadog::Tracing.correlation.

Motivation:

I am developing a Rails application utilizing types with Steep/RBS.
Since the type definitions for the datadog gem were incomplete, I added the missing type definitions.

Additional Notes:

How to test the change?

No application code has been changed.
I have confirmed that steep check passes successfully.

[github-actions]

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^{Visited at: 2025-03-27 20:27:10 UTC}

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-03-27 20:40:51

Comparing candidate commit 641d1b9 in PR branch add-correlation-rbs with baseline commit c0a829b in branch master.

Found 1 performance improvements and 1 performance regressions! Performance is the same for 29 metrics, 2 unstable metrics.

scenario:tracing - Propagation - Datadog

• 🟥 throughput [-2587.489op/s; -2511.315op/s] or [-8.096%; -7.858%]

scenario:tracing - Propagation - Trace Context

• 🟩 throughput [+4356.839op/s; +4468.945op/s] or [+12.924%; +13.256%]

[datadog-datadog-prod-us1]

Datadog Report

Branch report: add-correlation-rbs
Commit report: 641d1b9
Test service: dd-trace-rb

✅ 0 Failed, 20592 Passed, 1370 Skipped, 3m 24.07s Total Time