lint: avoid mypy warning in _pq_ctypes.py

I can't find how my editor is set up, but it doesn't complain on this
file, and yet calling mypy on this file only will find several error.

Having seen @dlax adding `type: ignore[no-any-return]` comments makes me
want to fix this.

Author: dvarrazzo

psycopg/psycopg/pq/_pq_ctypes.py

@@ -9,7 +9,7 @@
 import ctypes.util
 from ctypes import Structure, CFUNCTYPE, POINTER
 from ctypes import c_char, c_char_p, c_int, c_size_t, c_ubyte, c_uint, c_void_p
-from typing import List, Optional, Tuple
+from typing import Any, List, Optional, Tuple
 
 from .misc import find_libpq_full_path
 from ..errors import NotSupportedError
@@ -200,7 +200,8 @@ def PQhostaddr(pgconn: PGconn_struct) -> bytes:
             f" {libpq_version} available instead"
         )
 
-    return _PQhostaddr(pgconn)
+    rv: bytes = _PQhostaddr(pgconn)
+    return rv
 
 
 PQport = pq.PQport
@@ -324,7 +325,8 @@ def PQclosePrepared(pgconn: PGconn_struct, name: str) -> int:
             "PQclosePrepared requires libpq from PostgreSQL 17,"
             f" {libpq_version} available instead"
         )
-    return _PQclosePrepared(pgconn, name)
+    rv: int = _PQclosePrepared(pgconn, name)
+    return rv
 
 
 def PQclosePortal(pgconn: PGconn_struct, name: str) -> int:
@@ -333,7 +335,8 @@ def PQclosePortal(pgconn: PGconn_struct, name: str) -> int:
             "PQclosePortal requires libpq from PostgreSQL 17,"
             f" {libpq_version} available instead"
         )
-    return _PQclosePortal(pgconn, name)
+    rv: int = _PQclosePortal(pgconn, name)
+    return rv
 
 
 PQresultStatus = pq.PQresultStatus
@@ -548,7 +551,8 @@ def PQsendClosePrepared(pgconn: PGconn_struct, name: str) -> int:
             "PQsendClosePrepared requires libpq from PostgreSQL 17,"
             f" {libpq_version} available instead"
         )
-    return _PQsendClosePrepared(pgconn, name)
+    rv: int = _PQsendClosePrepared(pgconn, name)
+    return rv
 
 
 def PQsendClosePortal(pgconn: PGconn_struct, name: str) -> int:
@@ -557,7 +561,8 @@ def PQsendClosePortal(pgconn: PGconn_struct, name: str) -> int:
             "PQsendClosePortal requires libpq from PostgreSQL 17,"
             f" {libpq_version} available instead"
         )
-    return _PQsendClosePortal(pgconn, name)
+    rv: int = _PQsendClosePortal(pgconn, name)
+    return rv
 
 
 PQgetResult = pq.PQgetResult
@@ -683,7 +688,8 @@ def PQencryptPasswordConn(
             f" {libpq_version} available instead"
         )
 
-    return _PQencryptPasswordConn(pgconn, passwd, user, algorithm)
+    rv: Optional[bytes] = _PQencryptPasswordConn(pgconn, passwd, user, algorithm)
+    return rv
 
 
 PQmakeEmptyPGresult = pq.PQmakeEmptyPGresult
@@ -739,7 +745,8 @@ def PQpipelineStatus(pgconn: PGconn_struct) -> int:
             "PQpipelineStatus requires libpq from PostgreSQL 14,"
             f" {libpq_version} available instead"
         )
-    return _PQpipelineStatus(pgconn)
+    rv: int = _PQpipelineStatus(pgconn)
+    return rv
 
 
 def PQenterPipelineMode(pgconn: PGconn_struct) -> int:
@@ -748,7 +755,8 @@ def PQenterPipelineMode(pgconn: PGconn_struct) -> int:
             "PQenterPipelineMode requires libpq from PostgreSQL 14,"
             f" {libpq_version} available instead"
         )
-    return _PQenterPipelineMode(pgconn)
+    rv: int = _PQenterPipelineMode(pgconn)
+    return rv
 
 
 def PQexitPipelineMode(pgconn: PGconn_struct) -> int:
@@ -757,7 +765,8 @@ def PQexitPipelineMode(pgconn: PGconn_struct) -> int:
             "PQexitPipelineMode requires libpq from PostgreSQL 14,"
             f" {libpq_version} available instead"
         )
-    return _PQexitPipelineMode(pgconn)
+    rv: int = _PQexitPipelineMode(pgconn)
+    return rv
 
 
 def PQpipelineSync(pgconn: PGconn_struct) -> int:
@@ -766,7 +775,8 @@ def PQpipelineSync(pgconn: PGconn_struct) -> int:
             "PQpipelineSync requires libpq from PostgreSQL 14,"
             f" {libpq_version} available instead"
         )
-    return _PQpipelineSync(pgconn)
+    rv: int = _PQpipelineSync(pgconn)
+    return rv
 
 
 def PQsendFlushRequest(pgconn: PGconn_struct) -> int:
@@ -775,7 +785,8 @@ def PQsendFlushRequest(pgconn: PGconn_struct) -> int:
             "PQsendFlushRequest requires libpq from PostgreSQL 14,"
             f" {libpq_version} available instead"
         )
-    return _PQsendFlushRequest(pgconn)
+    rv: int = _PQsendFlushRequest(pgconn)
+    return rv
 
 
 # 33.18. SSL Support
@@ -787,9 +798,9 @@ def PQsendFlushRequest(pgconn: PGconn_struct) -> int:
 
 def generate_stub() -> None:
     import re
-    from ctypes import _CFuncPtr  # type: ignore
+    from ctypes import _CFuncPtr  # type: ignore[attr-defined]
 
-    def type2str(fname, narg, t):
+    def type2str(fname: str, narg: int | None, t: Any) -> str:
         if t is None:
             return "None"
         elif t is c_void_p:
@@ -810,7 +821,7 @@ def type2str(fname, narg, t):
             if narg is not None:
                 return f"Optional[{t.__name__[3:]}]"
             else:
-                return t.__name__[3:]
+                return str(t.__name__[3:])
 
         elif t.__name__ in ("LP_PQconninfoOption_struct",):
             return f"Sequence[{t.__name__[3:]}]"