Mostly it's about Go 1.22+ syntax with ranging over integers, but it also
prefers ranging over slices where possible (it makes code a little better to
read).
Notice that we have a number of dangerous loops where slices are mutated
during loop execution, many of these can't be converted since we need proper
length evalutation at every iteration.
Signed-off-by: Roman Khimov <roman@nspcc.ru>
