NIFI-7075 Add missing FlowFile core attributes to Developer Guide (#4030)
NIFI-7075 Add missing FlowFile core attributes to Developer Guide (#4030)

Signed-off-by: Andy LoPresto <feb3cf00ee9bc01575e9428a4270e7b599f5a4bd@apache.org>
mattyb149/nifi,ijokarumawak/nifi,pvillard31/nifi,mcgilman/nifi,YolandaMDavis/nifi,MikeThomsen/nifi,pvillard31/nifi,mattyb149/nifi,mattyb149/nifi,patricker/nifi,alopresto/nifi,pvillard31/nifi,trixpan/nifi,alopresto/nifi,alopresto/nifi,mcgilman/nifi,patricker/nifi,trixpan/nifi,jfrazee/nifi,mcgilman/nifi,MikeThomsen/nifi,ijokarumawak/nifi,YolandaMDavis/nifi,patricker/nifi,MikeThomsen/nifi,patricker/nifi,jfrazee/nifi,jfrazee/nifi,m-hogue/nifi,mattyb149/nifi,YolandaMDavis/nifi,m-hogue/nifi,mattyb149/nifi,jfrazee/nifi,jfrazee/nifi,m-hogue/nifi,jfrazee/nifi,jtstorck/nifi,alopresto/nifi,trixpan/nifi,trixpan/nifi,MikeThomsen/nifi,ijokarumawak/nifi,aperepel/nifi,aperepel/nifi,aperepel/nifi,trixpan/nifi,patricker/nifi,alopresto/nifi,jtstorck/nifi,pvillard31/nifi,trixpan/nifi,jtstorck/nifi,pvillard31/nifi,MikeThomsen/nifi,jfrazee/nifi,YolandaMDavis/nifi,pvillard31/nifi,alopresto/nifi,m-hogue/nifi,alopresto/nifi,ijokarumawak/nifi,ijokarumawak/nifi,jtstorck/nifi,pvillard31/nifi,jtstorck/nifi,mattyb149/nifi,YolandaMDavis/nifi,mcgilman/nifi,m-hogue/nifi,mcgilman/nifi,aperepel/nifi,jtstorck/nifi,patricker/nifi,jtstorck/nifi,ijokarumawak/nifi,pvillard31/nifi,YolandaMDavis/nifi,aperepel/nifi,MikeThomsen/nifi,YolandaMDavis/nifi,aperepel/nifi,jfrazee/nifi,m-hogue/nifi,patricker/nifi,mcgilman/nifi,mattyb149/nifi,mcgilman/nifi,m-hogue/nifi,MikeThomsen/nifi