DOC: More pipeline docstring tweaks
DOC: More pipeline docstring tweaks

magne-max/zipline-ja,enigmampc/catalyst,bartosh/zipline,florentchandelier/zipline,quantopian/zipline,magne-max/zipline-ja,Scapogo/zipline,florentchandelier/zipline,humdings/zipline,humdings/zipline,bartosh/zipline,enigmampc/catalyst,alphaBenj/zipline,Scapogo/zipline,quantopian/zipline,alphaBenj/zipline