Add more thread details #2409

[thompson-tomo]

Fixes #2409

Changes

Introduces more details about the thread being described.

Note: if the PR is touching an area that is not listed in the existing areas, or the area does not have sufficient domain experts coverage, the PR might be tagged as experts needed and move slowly until experts are identified.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.

[joaopgrassi]

Is there any background in why you want these fields added? Is there instrumentation work wanting these fields? I tried to look at ECS and there it is also not defined, which makes me wonder how relevant these really are. CC @open-telemetry/semconv-system-approvers

[thompson-tomo]

I see them as useful metadata to provide additional context about why things might have taken as long as they did.

The priority would be useful addition to https://opentelemetry.io/docs/specs/semconv/runtime/go-metrics/#metric-goscheduleduration for example and also metrics about locks