How to navigate to next git conflict?

[Hi-Angel]

For working with git I noted one of frequent actions I do is resolving
conflicts. I'm comfortable to work with most of that from terminal
(I've got a completion in zsh and what not…) except that conflict
navigation could use a bit of automation.

So far I only managed to find `smerge-next`, but it is limited to the
focused buffer, in there I can as well search for a HEAD or <<<
markers, so not really useful.