Convention sweep (user req): all `tractor.open_nursery()`
bindings in test + example code use `an: ActorNursery` (`n`,
`nursery` + several tractor-nurseries confusingly named `tn`
are renamed); `trio.open_nursery()` bindings stay `tn` (incl.
`concurrent_actors_primes.py`'s inner trio nursery, renamed
`n` -> `tn` to match).
Purely mechanical, function-scoped renames — prose "nursery"/
"an" in docstrings/comments untouched; func-arg kwargs like
`portal.run(func, n=value)` untouched.
Gate: renamed test modules green on `trio`; full debugger suite
(28p/6s) + example-runner (21p) green.
(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).