obslog: use singular name "succnode" for each element of {succnodes} The name that we pass for formatlist() is the name of each element. After this patch, you'll write '{succnodes % "{succnode}"}' instead of the confusing '{succnodes % "{succnodes}"}' (where the two "succnodes" refer to different things. Users can write templates that are compatible across this change by using e.g. '{succnodes % "{if(succnode, succnode, succnodes)}"}'.

docs: add SVG figures for sharing.rst Generated by graphviz loosely based on .dot files produced by dotgraph extension.