obslog: rename {desc-diff} to {descdiff} since the former is invalid

tests: demonstrate broken {patch} and {desc-diff} template keywords

topic: drop compat.successorssets(), it's not used The only place in topics that uses successorssets function is in evolvebits.py, and it's using that function from obsutil directly.

topic: drop compat.getmarkers() and use obsutil.getmarkers() directly The function in question was moved from obsolete to obsutil in a14e2e7f7d1f (hg 4.3). See also 6aff4bb3970d for hgext3rd/evolve.

cmdrewrite: avoid accessing scmutil.status fields by index Support for indexed access is going away in Mercurial. Accessing the fields by name is clearer anyway.

obslog: avoid using a formatter after calling end() on it I don't know if makes a difference, but it feels wrong to use it after calling end(). We can simply use the parent formatter in this case.

obslog: use plural name "effects" for list of all effects Same reasoning as the previous patch, but here the singular was used for the list instead. This patch also renames the variable that represents the list of effects to plural "effects" to reduce confusion.

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.

docs: add some up-to-date output from push/pull commands Hopefully it's going to be helpful for users to better understand how evolve works.