fix doc typo
fix doc typo

BS3 commits: e9982cad66839f82515079912f207ee1b9708f9d

2947721120/todc-bootstrap,mozillo/todc-bootstrap,todc/todc-bootstrap,todc/todc-bootstrap,up2vs/todc-bootstrap,aaroncnhk/todc-bootstrap,ztx1491/todc-bootstrap,todc/todc-bootstrap,2947721120/googlebt4