Add upstream SGLang PR links to perf-changelog.yaml for qwen3.5 MI355X entry

Co-authored-by: functionstackx <functionstackx@users.noreply.github.com>

Author: github-actions[bot]

perf-changelog.yaml

@@ -1365,4 +1365,5 @@
   description:
     - "Update cli args of Qwen3.5 FP8 and BF16 SGLang benchmarks for MI355X to achieve better performance"
     - "Use lmsysorg/sglang-rocm:v0.5.10rc0-rocm720-mi35x-20260415"
+    - "Image includes upstream SGLang PRs: https://github.com/sgl-project/sglang/pull/21188, https://github.com/sgl-project/sglang/pull/21421, https://github.com/sgl-project/sglang/pull/20736"
   pr-link: https://github.com/SemiAnalysisAI/InferenceX/pull/1036