fixing doc bug for using Bootstrap custom CSS
fixing doc bug for using Bootstrap custom CSS

thuongdoannguyen/thuongdoannguyen.github.io,frafra/ProntoSoccorsoLiguria,alexjstubbs/ignition-dev,thuongdoannguyen/thuongdoannguyen.github.io,alexjstubbs/ignition-dev,alexjstubbs/ignition-dev,alexjstubbs/ignition-dev,thuongdoannguyen/thuongdoannguyen.github.io,frafra/ProntoSoccorsoLiguria,alexjstubbs/ignition-dev