Add basic typing to the `debugging/` examples

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

examples/debugging/fast_error_in_root_after_spawn.py

@@ -35,7 +35,7 @@ async def open_ctx(
         assert first is None
 
 
-async def main():
+async def main() -> None:
 
     async with tractor.open_nursery(
         debug_mode=True,

examples/debugging/multi_daemon_subactors.py

@@ -20,7 +20,7 @@ async def name_error():
     getattr(doggypants)  # noqa
 
 
-async def main():
+async def main() -> None:
     '''
     Test breakpoint in a streaming actor.
 

examples/debugging/multi_nested_subactors_error_up_through_nurseries.py

@@ -21,6 +21,7 @@ async def breakpoint_forever():
 async def spawn_until(depth=0):
     """"A nested nursery that triggers another ``NameError``.
     """
+    n: tractor.ActorNursery
     async with tractor.open_nursery() as n:
         if depth < 1:
 
@@ -46,7 +47,7 @@ async def spawn_until(depth=0):
 
 
 # TODO: notes on the new boxed-relayed errors through proxy actors
-async def main():
+async def main() -> None:
     """The main ``tractor`` routine.
 
     The process tree should look as approximately as follows when the debugger

examples/debugging/multi_subactor_root_errors.py

@@ -15,6 +15,7 @@ async def name_error():
 async def spawn_error():
     """"A nested nursery that triggers another ``NameError``.
     """
+    n: tractor.ActorNursery
     async with tractor.open_nursery() as n:
         portal = await n.run_in_actor(
             name_error,
@@ -23,7 +24,7 @@ async def spawn_error():
         return await portal.result()
 
 
-async def main():
+async def main() -> None:
     """The main ``tractor`` routine.
 
     The process tree should look as approximately as follows:

examples/debugging/multi_subactors.py

@@ -17,6 +17,7 @@ async def name_error():
 async def spawn_error():
     """"A nested nursery that triggers another ``NameError``.
     """
+    n: tractor.ActorNursery
     async with tractor.open_nursery() as n:
         portal = await n.run_in_actor(
             name_error,
@@ -25,7 +26,7 @@ async def spawn_error():
         return await portal.result()
 
 
-async def main():
+async def main() -> None:
     """The main ``tractor`` routine.
 
     The process tree should look as approximately as follows:

examples/debugging/per_actor_debug.py

@@ -5,7 +5,8 @@ async def die():
     raise RuntimeError
 
 
-async def main():
+async def main() -> None:
+    tn: tractor.ActorNursery
     async with tractor.open_nursery() as tn:
 
         debug_actor = await tn.start_actor(

examples/debugging/pm_in_subactor.py

@@ -18,7 +18,7 @@ async def name_error(
         raise
 
 
-async def main():
+async def main() -> None:
     '''
     Test 3 `PdbREPL` entries:
       - one in the child due to manual `.post_mortem()`,

examples/debugging/root_actor_breakpoint.py

@@ -2,7 +2,7 @@ import trio
 import tractor
 
 
-async def main():
+async def main() -> None:
 
     async with tractor.open_root_actor(
         debug_mode=True,

examples/debugging/root_actor_error.py

@@ -2,7 +2,7 @@ import trio
 import tractor
 
 
-async def main():
+async def main() -> None:
     async with tractor.open_root_actor(
         debug_mode=True,
     ):

examples/debugging/root_cancelled_but_child_is_in_tty_lock.py

@@ -10,6 +10,7 @@ async def name_error():
 async def spawn_until(depth=0):
     """"A nested nursery that triggers another ``NameError``.
     """
+    n: tractor.ActorNursery
     async with tractor.open_nursery() as n:
         if depth < 1:
             # await n.run_in_actor('breakpoint_forever', breakpoint_forever)
@@ -23,7 +24,7 @@ async def spawn_until(depth=0):
             )
 
 
-async def main():
+async def main() -> None:
     '''
     The process tree should look as approximately as follows when the
     debugger first engages:

examples/debugging/root_self_cancelled_w_error.py

@@ -2,7 +2,7 @@ import trio
 import tractor
 
 
-async def main():
+async def main() -> None:
     async with tractor.open_root_actor(
         debug_mode=True,
         loglevel='cancel',

examples/debugging/root_timeout_while_child_crashed.py

@@ -7,7 +7,7 @@ async def key_error():
     return {}['doggy']
 
 
-async def main():
+async def main() -> None:
     '''
     Root is fail-after-cancelled while blocking and child RPC fails
     simultaneously.

examples/debugging/shielded_pause.py

@@ -71,7 +71,7 @@ async def cancelled_before_pause(
     await pm_on_cancelled()
 
 
-async def main():
+async def main() -> None:
     async with tractor.open_nursery(
         debug_mode=True,
     ) as n:

examples/debugging/subactor_bp_in_ctx.py

@@ -34,7 +34,7 @@ async def just_bp(
 
 
 
-async def main():
+async def main() -> None:
 
     # !TODO, parametrize the --tpt-proto={key} with osenv vars just
     # like we do for loglevel/spawn-backend!

examples/debugging/subactor_breakpoint.py

@@ -12,7 +12,7 @@ async def breakpoint_forever():
         await tractor.pause()
 
 
-async def main():
+async def main() -> None:
 
     async with tractor.open_nursery(
         debug_mode=True,

examples/debugging/subactor_error.py

@@ -6,7 +6,7 @@ async def name_error():
     getattr(doggypants)  # noqa (on purpose)
 
 
-async def main():
+async def main() -> None:
     async with tractor.open_nursery(
         debug_mode=True,
     ) as an: