fix run error

Author: carolynzech

.github/workflows/kani.yml

@@ -66,12 +66,16 @@ jobs:
         working-directory: ${{github.workspace}}/head
         run: scripts/run-kani.sh --kani-args --harness ptr::verify::check_read_u128 --harness ptr --output-format=terse
 
-      # Step 3: Run list on the std library (assumes it creates kani_list.txt)
+      # Step 4: Run list on the std library and add output to job summary
       - name: Run Kani List
+        run: head/scripts/run-kani.sh --run list --path ${{github.workspace}}/head
+
+      - name: Add Kani List output to job summary
         uses: actions/github-script@v6
         with:
           script: |
-            head/scripts/run-kani.sh --run list --path ${{github.workspace}}/head;
             const fs = require('fs');
             const kaniOutput = fs.readFileSync('${{github.workspace}}/head/kani_list.txt', 'utf8');
-            kaniOutput >> "$GITHUB_STEP_SUMMARY";
+            await core.summary
+              .addRaw(kaniOutput)
+              .write();