Add stubs for entrypoints package (#5831)

stubs/entrypoints/METADATA.toml

@@ -0,0 +1,2 @@
+version = "0.3"
+python2 = true

stubs/entrypoints/entrypoints.pyi

@@ -0,0 +1,57 @@
+import sys
+from _typeshed import Self
+from typing import Any, Dict, Iterator, List, Sequence, Text, Tuple, Type
+
+if sys.version_info >= (3, 0):
+    from configparser import ConfigParser
+else:
+    from ConfigParser import ConfigParser
+
+if sys.version_info >= (3, 8):
+    from re import Pattern
+else:
+    from typing import Pattern
+
+entry_point_pattern: Pattern[Text]
+file_in_zip_pattern: Pattern[Text]
+
+class BadEntryPoint(Exception):
+    epstr: Text
+    def __init__(self, epstr: Text) -> None: ...
+    @staticmethod
+    def err_to_warnings() -> Iterator[None]: ...
+
+class NoSuchEntryPoint(Exception):
+    group: Text
+    name: Text
+    def __init__(self, group: Text, name: Text) -> None: ...
+
+class EntryPoint:
+    name: Text
+    module_name: Text
+    object_name: Text
+    extras: Sequence[Text] | None
+    distro: Distribution | None
+    def __init__(
+        self,
+        name: Text,
+        module_name: Text,
+        object_name: Text,
+        extras: Sequence[Text] | None = ...,
+        distro: Distribution | None = ...,
+    ) -> None: ...
+    def load(self) -> Any: ...
+    @classmethod
+    def from_string(cls: Type[Self], epstr: Text, name: Text, distro: Distribution | None = ...) -> Self: ...
+
+class Distribution:
+    name: Text
+    version: Text
+    def __init__(self, name: Text, version: Text) -> None: ...
+
+def iter_files_distros(
+    path: Sequence[Text] | None = ..., repeated_distro: Text = ...
+) -> Iterator[Tuple[ConfigParser, Distribution | None]]: ...
+def get_single(group: Text, name: Text, path: Sequence[Text] | None = ...) -> EntryPoint: ...
+def get_group_named(group: Text, path: Sequence[Text] | None = ...) -> Dict[str, EntryPoint]: ...
+def get_group_all(group: Text, path: Sequence[Text] | None = ...) -> List[EntryPoint]: ...