add href to sub-reports that have multiple headers to fix #270
add href to sub-reports that have multiple headers to fix #270

oesteban/fmriprep,poldracklab/fmriprep,oesteban/fmriprep,poldracklab/fmriprep,poldracklab/preprocessing-workflow,oesteban/preprocessing-workflow,oesteban/fmriprep,oesteban/preprocessing-workflow,poldracklab/preprocessing-workflow,poldracklab/fmriprep