[doc] highlight tracing feature

[wangchao1230]

Description

[doc] highlight tracing feature

All Promptflow Contribution checklist:

• The pull request does not introduce [breaking changes].
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.
• Create an issue and link to the pull request to get dedicated review from promptflow team. Learn more: suggested workflow.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• 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.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

promptflow SDK CLI Azure E2E Test Result clwan/highlight_tracing_feature

  4 files    4 suites   4m 20s ⏱️
244 tests 204 ✅  40 💤 0 ❌
976 runs  816 ✅ 160 💤 0 ❌

Results for commit b5b6563.

♻️ This comment has been updated with latest results.

[github-actions]

SDK CLI Global Config Test Result clwan/highlight_tracing_feature

6 tests   6 ✅  1m 19s ⏱️
1 suites  0 💤
1 files    0 ❌

Results for commit b5b6563.

♻️ This comment has been updated with latest results.

[github-actions]

Executor E2E Test Result clwan/highlight_tracing_feature

246 tests   240 ✅  5m 4s ⏱️
  1 suites    6 💤
  1 files      0 ❌

Results for commit b5b6563.

♻️ This comment has been updated with latest results.

[github-actions]

Executor Unit Test Result clwan/highlight_tracing_feature

796 tests   796 ✅  3m 46s ⏱️
  1 suites    0 💤
  1 files      0 ❌

Results for commit b5b6563.

♻️ This comment has been updated with latest results.