Update External Link Reference in trace-span-spec-reference.md (#3415)

# Description

This pull request updates an external link reference within a
`trace-span-spec-reference.md` to ensure accuracy and relevance of the
documentation. The modification corrects the hyperlink to point to the
intended web resource.

# All Promptflow Contribution checklist:
- [X] **The pull request does not introduce [breaking changes].**
- [ ] **CHANGELOG is updated for new features, bug fixes or other
significant changes.**
- [X] **I have read the [contribution guidelines](../CONTRIBUTING.md).**
- [ ] **Create an issue and link to the pull request to get dedicated
review from promptflow team. Learn more: [suggested
workflow](../CONTRIBUTING.md#suggested-workflow).**

## General Guidelines and Best Practices
- [X] Title of the pull request is clear and informative.
- [X] There are a small number of commits, each of which have an
informative message. This means that previously merged commits do not
appear in the history of the PR. For more information on cleaning up the
commits in your PR, [see this
page](https://github.com/Azure/azure-powershell/blob/master/documentation/development-docs/cleaning-up-commits.md).

### Testing Guidelines
- [X] Pull request includes test coverage for the included changes.

docs/reference/trace-span-spec-reference.md

@@ -95,7 +95,7 @@ The LLM (Large Language Model) span captures detailed execution information from
 |---|---|---|---|
 | promptflow.llm.generated_message | Captures the output message from an LLM call. | ```{"content":"ChatGPT is a conversational AI model developed by OpenAI.","role":"assistant","function_call":null,"tool_calls":null}``` | `Required` |
 
->Note: OpenTelemetry currently defines several LLM-related span attributes and events as semantic conventions. We plan to align with these conventions in the future. For more information, visit [LLM Semantic Conventions](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/gen-ai/llm-spans.md).
+>Note: OpenTelemetry currently defines several LLM-related span attributes and events as semantic conventions. We plan to align with these conventions in the future. For more information, visit [Semantic Conventions for GenAI operations](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/gen-ai/gen-ai-spans.md).
 
 #### Function