Fix docstrings not exposed on public API.

src/debugpy/public_api.py

@@ -3,6 +3,7 @@
 # for license information.
 
 from __future__ import annotations
+import functools
 import typing
 
 from debugpy import _version
@@ -24,6 +25,7 @@ if typing.TYPE_CHECKING:
 
 def _api(cancelable=False):
     def apply(f):
+        @functools.wraps(f)
         def wrapper(*args, **kwargs):
             from debugpy.server import api
 

tests/debugpy/test_docstrings.py

@@ -14,5 +14,6 @@ def test_docstrings():
         member = getattr(debugpy, attr)
 
         doc = inspect.getdoc(member)
+        assert doc is not None, f"debugpy.{member} doesn't have a docstring"
         for lineno, line in enumerate(doc.split("\n")):
             assert len(line) <= 72