Re: [PATCH 4/6] git-sparse-checkout.txt: update to document that set handles init

>> +'init'::
>> +	Deprecated command that behaves like `set` with no specified paths.
>> +	May be removed in the future.
> 
> I'm on board with deprecating `init`, but one usage that's not covered by
> the updated `set` is toggling the sparse index *without* modifying the
> patterns. That likely won't matter to most users, but ones that assume `git
> sparse-checkout set --[no-]sparse-index` works the same way as `git
> sparse-checkout init --[no-]sparse-index` would find themselves losing their
> existing pattern set.
> 
> Maybe `--[no-]sparse-index` should be added to `git sparse-checkout
> reapply`? For changing settings without updating patterns, that probably
> makes more sense than `init` or `set` anyway. If adding that option is
> outside the scope of what you want to do in this series, though, I'd be
> happy with a note somewhere in this documentation explicitly noting that
> `set` (unlike `init`) will change your patterns, even when toggling
> `index.sparse` (or `core.sparseCheckoutCone`).