chore(ci): presubmit-pr-888 adds Closes #888 on merge

Closes #1234

scripts/ci/presubmit-queue-success.sh

@@ -22,6 +22,15 @@ if [ "$TRAVIS_REPO_SLUG" = "angular/angular" ]; then
     git stash
     git fetch upstream master
     git rebase upstream/master
+
+    if [[ $TRAVIS_BRANCH == *"-pr-"* ]]; then
+      PR_NO=`echo presubmit-mhevery-pr-1234 | sed -e 's/^.*-pr-//'`
+      if echo $PR_NO | egrep -q '^[0-9]+$'; then
+        echo "Adding Closes #$PR_NO"
+        git filter-branch -f --msg-filter "cat /dev/stdin && echo && echo Closes \#$PR_NO" HEAD~1..HEAD
+      fi
+    fi
+
     if git push upstream HEAD:master; then
       echo "$TRAVIS_BRANCH has been merged into master, deleting..."
       git push upstream :"$TRAVIS_BRANCH"