psycopg2: stub improvements (#7964)

Fixes an entry from #7928 along with a number of other improvements.

I went off the C code:
https://github.com/psycopg/psycopg2/blob/master/psycopg/connection_type.c

stubs/psycopg2/psycopg2/_psycopg.pyi

@@ -2,7 +2,7 @@ from _typeshed import Self
 from collections.abc import Callable, Iterable, Mapping, Sequence
 from types import TracebackType
 from typing import Any, TypeVar, overload
-from typing_extensions import TypeAlias
+from typing_extensions import Literal, TypeAlias
 
 import psycopg2
 import psycopg2.extensions
@@ -82,13 +82,13 @@ class cursor:
     row_factory: Any
     rowcount: int
     rownumber: int
-    scrollable: Any
+    scrollable: bool | None
     statusmessage: Any
     string_types: Any
     typecaster: Any
     tzinfo_factory: Any
-    withhold: Any
-    def __init__(self, *args, **kwargs) -> None: ...
+    withhold: bool
+    def __init__(self, conn: connection, name: str | bytes | None = ...) -> None: ...
     def callproc(self, procname, parameters=...): ...
     def cast(self, oid, s): ...
     def close(self): ...
@@ -371,64 +371,99 @@ class connection:
     ProgrammingError: Any
     Warning: Any
     @property
-    def async_(self) -> Any: ...
-    autocommit: Any
+    def async_(self) -> int: ...
+    autocommit: bool
     @property
     def binary_types(self) -> Any: ...
     @property
-    def closed(self) -> Any: ...
+    def closed(self) -> int: ...
     cursor_factory: Callable[..., _cursor]
-    deferrable: Any
     @property
-    def dsn(self) -> Any: ...
+    def dsn(self) -> str: ...
     @property
-    def encoding(self) -> Any: ...
+    def encoding(self) -> str: ...
     @property
     def info(self) -> ConnectionInfo: ...
-    isolation_level: Any
-    notices: Any
-    notifies: Any
     @property
-    def pgconn_ptr(self) -> Any: ...
+    def isolation_level(self) -> int | None: ...
+    @isolation_level.setter
+    def isolation_level(self, __value: str | bytes | int | None) -> None: ...
+    notices: list[Any]
+    notifies: list[Any]
+    @property
+    def pgconn_ptr(self) -> int | None: ...
     @property
     def protocol_version(self) -> int: ...
-    readonly: Any
+    @property
+    def deferrable(self) -> bool | None: ...
+    @deferrable.setter
+    def deferrable(self, __value: Literal["default"] | bool | None) -> None: ...
+    @property
+    def readonly(self) -> bool | None: ...
+    @readonly.setter
+    def readonly(self, __value: Literal["default"] | bool | None) -> None: ...
     @property
     def server_version(self) -> int: ...
     @property
-    def status(self) -> Any: ...
+    def status(self) -> int: ...
     @property
     def string_types(self) -> Any: ...
-    def __init__(self, *args, **kwargs) -> None: ...
-    def cancel(self, *args, **kwargs): ...
-    def close(self, *args, **kwargs): ...
-    def commit(self, *args, **kwargs): ...
+    # Really it's dsn: str, async: int = ..., async_: int = ..., but
+    # that would be a syntax error.
+    def __init__(self, dsn: str, *, async_: int = ...) -> None: ...
+    def cancel(self) -> None: ...
+    def close(self) -> None: ...
+    def commit(self) -> None: ...
     @overload
-    def cursor(self, name=..., *, scrollable=..., withhold=...) -> _cursor: ...
+    def cursor(self, name: str | bytes | None = ..., *, withhold: bool = ..., scrollable: bool | None = ...) -> _cursor: ...
     @overload
-    def cursor(self, name=..., cursor_factory: Callable[..., _T_cur] = ..., scrollable=..., withhold=...) -> _T_cur: ...
-    def fileno(self, *args, **kwargs): ...
+    def cursor(
+        self,
+        name: str | bytes | None = ...,
+        *,
+        cursor_factory: Callable[..., _T_cur],
+        withhold: bool = ...,
+        scrollable: bool | None = ...,
+    ) -> _T_cur: ...
+    @overload
+    def cursor(
+        self, name: str | bytes | None, cursor_factory: Callable[..., _T_cur], withhold: bool = ..., scrollable: bool | None = ...
+    ) -> _T_cur: ...
+    def fileno(self) -> int: ...
     def get_backend_pid(self) -> int: ...
     def get_dsn_parameters(self) -> dict[str, str]: ...
-    def get_native_connection(self, *args, **kwargs): ...
+    def get_native_connection(self): ...
     def get_parameter_status(self, parameter: str) -> str | None: ...
     def get_transaction_status(self) -> int: ...
-    def isexecuting(self, *args, **kwargs): ...
-    def lobject(self, oid=..., mode=..., new_oid=..., new_file=..., lobject_factory=...): ...
-    def poll(self, *args, **kwargs): ...
-    def reset(self): ...
-    def rollback(self): ...
-    def set_client_encoding(self, encoding): ...
-    def set_isolation_level(self, level): ...
-    def set_session(self, *args, **kwargs): ...
-    def tpc_begin(self, xid): ...
-    def tpc_commit(self, *args, **kwargs): ...
-    def tpc_prepare(self): ...
-    def tpc_recover(self): ...
-    def tpc_rollback(self, *args, **kwargs): ...
-    def xid(self, format_id, gtrid, bqual): ...
-    def __enter__(self): ...
-    def __exit__(self, type, value, traceback): ...
+    def isexecuting(self) -> bool: ...
+    def lobject(
+        self,
+        oid: int = ...,
+        mode: str | None = ...,
+        new_oid: int = ...,
+        new_file: str | None = ...,
+        lobject_factory: type[lobject] = ...,
+    ) -> lobject: ...
+    def poll(self) -> int: ...
+    def reset(self) -> None: ...
+    def rollback(self) -> None: ...
+    def set_client_encoding(self, encoding: str) -> None: ...
+    def set_isolation_level(self, level: int | None) -> None: ...
+    def set_session(
+        self,
+        isolation_level: str | bytes | int | None = ...,
+        readonly: bool | Literal["default", b"default"] | None = ...,
+        deferrable: bool | Literal["default", b"default"] | None = ...,
+        autocommit: bool = ...,
+    ) -> None: ...
+    def tpc_begin(self, xid: str | bytes | Xid) -> None: ...
+    def tpc_commit(self, __xid: str | bytes | Xid = ...) -> None: ...
+    def tpc_prepare(self) -> None: ...
+    def tpc_recover(self) -> list[Xid]: ...
+    def tpc_rollback(self, __xid: str | bytes | Xid = ...) -> None: ...
+    def xid(self, format_id, gtrid, bqual) -> Xid: ...
+    def __enter__(self: Self) -> Self: ...
+    def __exit__(self, __type: object, __name: object, __tb: object) -> None: ...
 
 class lobject:
     closed: Any