Drop non-collaborator acknowledgment from PR body

Filtering out non-collaborator reviewers stays (prevents the 422
whole-call-failure). But mentioning them by name in the augmented PR
body adds notification surface we don't want. Silently skip.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: rdimitrov

.github/workflows/upstream-release-docs.yml

@@ -384,31 +384,23 @@ jobs:
           # `gh pr edit --add-reviewer` call and drop the valid
           # reviewers along with the invalid ones. Community
           # contributors from the upstream repo often aren't
-          # collaborators on docs-website; silently skip them rather
-          # than ping or fail.
+          # collaborators here; silently skip them.
           CANDIDATES=$(echo "$COMPARE" |
             grep -Ev '(\[bot\]$|^github-actions|^stacklokbot$|^dependabot|^renovate|^copilot)' || true)
 
           REVIEWERS=""
-          SKIPPED=""
           while IFS= read -r login; do
             [ -z "$login" ] && continue
             if gh api "repos/$REVIEW_REPO/collaborators/$login" --silent 2>/dev/null; then
               REVIEWERS="${REVIEWERS:+$REVIEWERS,}$login"
-            else
-              SKIPPED="${SKIPPED:+$SKIPPED, }$login"
             fi
           done <<< "$CANDIDATES"
 
           # Cap at 5 to avoid review fatigue.
           REVIEWERS=$(echo "$REVIEWERS" | tr ',' '\n' | head -5 | paste -sd, -)
 
           echo "list=$REVIEWERS" >> "$GITHUB_OUTPUT"
-          echo "skipped=$SKIPPED" >> "$GITHUB_OUTPUT"
           echo "Reviewers: ${REVIEWERS:-<none>}"
-          if [ -n "$SKIPPED" ]; then
-            echo "Skipped non-collaborator contributors: $SKIPPED"
-          fi
 
       - name: Read docs_paths hint
         id: hints
@@ -597,7 +589,6 @@ jobs:
           GAPS_BLOCK: ${{ steps.signals.outputs.gaps_block }}
           AUTOGEN_NOTE: ${{ steps.autogen.outputs.note }}
           COMPARE_OK: ${{ steps.reviewers.outputs.compare_ok }}
-          SKIPPED_REVIEWERS: ${{ steps.reviewers.outputs.skipped }}
         run: |
           START='<!-- upstream-release-docs:start -->'
           END='<!-- upstream-release-docs:end -->'
@@ -633,10 +624,6 @@ jobs:
             fi
             echo "Reviewers below are non-bot commit authors in the release range who are also collaborators on this repo."
             echo ""
-            if [ -n "$SKIPPED_REVIEWERS" ]; then
-              echo "Other release contributors (not assigned as reviewers because they aren't repo collaborators): $SKIPPED_REVIEWERS. Thanks for the contribution!"
-              echo ""
-            fi
             echo "$END"
           } > /tmp/section.md