Sweep the `examples/debugging/` set for basic typing: add `-> None`
to all 16 bare `async def main()`s and annotate the clean
single-line `open_nursery()` bindings as `tractor.ActorNursery`.
Kept to the unambiguous, runtime-safe cases (these breakpoint/crash
demos can't be run headless); the heterogeneous
multi-line/paren-group nursery bindings + `current_actor()` returns
are left for a later pass. Continues the examples-typing bullet in
#472.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
This resolves and completes #69 allowing all RPC invocation APIs to pass
function references directly instead of explicit `str` names for the
target namespace and function (this is still done implicitly
underneath). This brings us closer to `trio`'s task running API as well
as acknowledges that any inter-host RPC system (and API) will likely
need to be implemented on top of local RPC primitives anyway. Even if
this ends up **not** being true we can always go to "function stubs" as
part of our IAC protocol or, add a new method to do explicit namespace
calls: `.run_from_module()` or whatever everyone votes on.
Resolves#69
Further, this commit drops `Actor.statespace` from the entire system
since a user can easily get this same functionality using module
level variables. Fix docs to match all these changes (luckily mostly
already done due to example scripts referencing).