fix: pub mod actor exposing SyncHandle (#52)

## Description

publishes the `actor` mod exposing SyncHandle, which is not exposed thus
it renders it unusable for users
Check
https://docs.rs/iroh-docs/latest/iroh_docs/engine/struct.Engine.html#structfield.sync

## Breaking Changes

There should be no breaking changes.

## Notes & open questions

None.

## Change checklist

- [x] Self-review.
- [x] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.
- [ ] Tests if relevant.
- [x] All breaking changes documented.

Co-authored-by: Philipp Krüger <philipp.krueger1@gmail.com>

Author: dgrr

src/actor.rs

@@ -238,6 +238,7 @@ pub struct OpenOpts {
     /// Optionally subscribe to replica events.
     pub subscribe: Option<async_channel::Sender<Event>>,
 }
+
 impl OpenOpts {
     /// Set sync state to true.
     pub fn sync(mut self) -> Self {

src/lib.rs

@@ -42,7 +42,7 @@ mod ticket;
 
 pub mod engine;
 
-mod actor;
+pub mod actor;
 pub mod api;
 pub mod store;
 pub mod sync;