Adjust restore-bp-ex import path to `.devx.debug`

Reversion of original cherry-pick fix from downstream history;
`.devx.debug` is now legit here.

examples/debugging/restore_builtin_breakpoint.py

@@ -5,7 +5,7 @@ import trio
 import tractor
 
 # ensure mod-path is correct!
-from tractor.devx._debug import (
+from tractor.devx.debug import (
     _sync_pause_from_builtin as _sync_pause_from_builtin,
 )
 

pyproject.toml

@@ -63,6 +63,7 @@ dev = [
   "stackscope>=0.2.2,<0.3",
   # ^ requires this?
   "typing-extensions>=4.14.1",
+
   "pyperclip>=1.9.0",
   "prompt-toolkit>=3.0.50",
   "xonsh>=0.19.2",