Sources. Small fixes to Problem, Step list

...patterns/00-atoms/01-text/paragraph-with-sources.mustache

source/_patterns/00-atoms/01-text/source.mustache

source/_patterns/00-atoms/04-lists/steps-list.mustache

...ns/01-molecules/25-problems/problems-pirati-stan.mustache

...lition-program-points/detail-program-pirati-stan.mustache

source/css/atoms/list-pirati-stan.pcss

source/css/atoms/paragraph.pcss