[liquid_tags] make docs python 2 and 3 compatible
[liquid_tags] make docs python 2 and 3 compatible

instructions were python2 only

mortada/pelican-plugins,xsteadfastx/pelican-plugins,mortada/pelican-plugins,rlaboiss/pelican-plugins,rlaboiss/pelican-plugins,talha131/pelican-plugins,MarkusH/pelican-plugins,talha131/pelican-plugins,xsteadfastx/pelican-plugins,rlaboiss/pelican-plugins,UHBiocomputation/pelican-plugins,MarkusH/pelican-plugins,mikitex70/pelican-plugins,UHBiocomputation/pelican-plugins,mortada/pelican-plugins,mikitex70/pelican-plugins,UHBiocomputation/pelican-plugins,talha131/pelican-plugins,xsteadfastx/pelican-plugins,mikitex70/pelican-plugins,mikitex70/pelican-plugins,MarkusH/pelican-plugins,mortada/pelican-plugins,xsteadfastx/pelican-plugins,MarkusH/pelican-plugins,talha131/pelican-plugins,MarkusH/pelican-plugins,talha131/pelican-plugins,mortada/pelican-plugins,rlaboiss/pelican-plugins,UHBiocomputation/pelican-plugins