Show error as list at the end of valgrind run

Co-authored-by: Vassil Vassilev <[email protected]>

.github/workflows/ci.yml

@@ -298,7 +298,7 @@ jobs:
           valgrind --error-exitcode=1 --suppressions=../etc/valgrind-cppyy-cling.supp python -m pytest -m "not xfail" -v || true
         else
           echo "Running valgrind on passing tests"
-          valgrind -s --error-exitcode=1 --suppressions=../etc/valgrind-cppyy-cling.supp python -m pytest -m "not xfail" -v
+          valgrind --show-error-list=yes --error-exitcode=1 --suppressions=../etc/valgrind-cppyy-cling.supp python -m pytest -m "not xfail" -v
         fi
         export RETCODE=+$?
         echo ::endgroup::