Update gettext translations (#7636)

* Use a protocol instead of `IO` for `fp` argument.
* Annotate a few missing return types.
* Mark some class constants as final.

Fixes #7628

stdlib/gettext.pyi

@@ -1,7 +1,8 @@
 import sys
 from _typeshed import StrPath
-from typing import IO, Any, Container, Iterable, Sequence, TypeVar, overload
-from typing_extensions import Literal
+from collections.abc import Container, Iterable, Sequence
+from typing import Any, Protocol, TypeVar, overload
+from typing_extensions import Final, Literal
 
 if sys.version_info >= (3, 11):
     __all__ = [
@@ -67,9 +68,14 @@ else:
         "ngettext",
     ]
 
+class _TranslationsReader(Protocol):
+    def read(self) -> bytes: ...
+    # optional:
+    # name: str
+
 class NullTranslations:
-    def __init__(self, fp: IO[str] | None = ...) -> None: ...
-    def _parse(self, fp: IO[str]) -> None: ...
+    def __init__(self, fp: _TranslationsReader | None = ...) -> None: ...
+    def _parse(self, fp: _TranslationsReader) -> None: ...
     def add_fallback(self, fallback: NullTranslations) -> None: ...
     def gettext(self, message: str) -> str: ...
     def lgettext(self, message: str) -> str: ...
@@ -79,18 +85,18 @@ class NullTranslations:
         def pgettext(self, context: str, message: str) -> str: ...
         def npgettext(self, context: str, msgid1: str, msgid2: str, n: int) -> str: ...
 
-    def info(self) -> Any: ...
-    def charset(self) -> Any: ...
+    def info(self) -> dict[str, str]: ...
+    def charset(self) -> str | None: ...
     if sys.version_info < (3, 11):
-        def output_charset(self) -> Any: ...
+        def output_charset(self) -> str | None: ...
         def set_output_charset(self, charset: str) -> None: ...
 
     def install(self, names: Container[str] | None = ...) -> None: ...
 
 class GNUTranslations(NullTranslations):
-    LE_MAGIC: int
-    BE_MAGIC: int
-    CONTEXT: str
+    LE_MAGIC: Final[int]
+    BE_MAGIC: Final[int]
+    CONTEXT: Final[str]
     VERSIONS: Sequence[int]
 
 @overload  # ignores incompatible overloads