adjust isort config (#4290)

Fixes #4288.

- Default imports to THIRD_PARTY, so in effect we merge the FIRST_PARTY and THIRD_PARTY stubs. This means import order is no longer affected by whether typing_extensions is installed locally.
- Treat typing_extensions, _typeshed and some others as standard library modules.

Note that isort master is very different from the latest release; we'll have to do something
different if and when the next isort release comes out.

stdlib/2/ConfigParser.pyi

@@ -1,6 +1,5 @@
-from typing import IO, Any, Dict, List, Optional, Sequence, Tuple, Union
-
 from _typeshed import SupportsReadline
+from typing import IO, Any, Dict, List, Optional, Sequence, Tuple, Union
 
 DEFAULTSECT: str
 MAX_INTERPOLATION_DEPTH: int

stdlib/2/__builtin__.pyi

@@ -2,6 +2,16 @@
 # Python 3, and stub files conform to Python 3 syntax.
 
 import sys
+from _typeshed import (
+    AnyPath,
+    OpenBinaryMode,
+    OpenBinaryModeReading,
+    OpenBinaryModeUpdating,
+    OpenBinaryModeWriting,
+    OpenTextMode,
+    ReadableBuffer,
+    SupportsWrite,
+)
 from abc import ABCMeta
 from ast import AST, mod
 from io import BufferedRandom, BufferedReader, BufferedWriter, FileIO, TextIOWrapper
@@ -46,20 +56,8 @@ from typing import (
     ValuesView,
     overload,
 )
-
 from typing_extensions import Literal
 
-from _typeshed import (
-    AnyPath,
-    OpenBinaryMode,
-    OpenBinaryModeReading,
-    OpenBinaryModeUpdating,
-    OpenBinaryModeWriting,
-    OpenTextMode,
-    ReadableBuffer,
-    SupportsWrite,
-)
-
 if sys.version_info >= (3,):
     from typing import SupportsBytes, SupportsRound
 

stdlib/2/compileall.pyi

@@ -1,6 +1,5 @@
-from typing import Any, Optional, Pattern
-
 from _typeshed import AnyPath
+from typing import Any, Optional, Pattern
 
 # rx can be any object with a 'search' method; once we have Protocols we can change the type
 def compile_dir(

stdlib/2/fcntl.pyi

@@ -1,6 +1,5 @@
-from typing import Any, Union
-
 from _typeshed import FileDescriptorLike
+from typing import Any, Union
 
 FASYNC: int
 FD_CLOEXEC: int

stdlib/2/json.pyi

@@ -1,6 +1,5 @@
-from typing import IO, Any, Callable, Dict, List, Optional, Text, Tuple, Type, Union
-
 from _typeshed import SupportsRead
+from typing import IO, Any, Callable, Dict, List, Optional, Text, Tuple, Type, Union
 
 class JSONDecodeError(ValueError):
     def dumps(self, obj: Any) -> str: ...

stdlib/2/os/__init__.pyi

@@ -1,4 +1,5 @@
 import sys
+from _typeshed import AnyPath
 from builtins import OSError as error
 from io import TextIOWrapper as _TextIOWrapper
 from posix import listdir as listdir, stat_result as stat_result  # TODO: use this, see https://github.com/python/mypy/issues/3078
@@ -25,8 +26,6 @@ from typing import (
     overload,
 )
 
-from _typeshed import AnyPath
-
 from . import path as path
 
 # We need to use something from path, or flake8 and pytype get unhappy

stdlib/2/os/path.pyi

@@ -1,11 +1,10 @@
 # NB: path.pyi and stdlib/2 and stdlib/3 must remain consistent!
 import os
 import sys
+from _typeshed import AnyPath, BytesPath, StrPath
 from genericpath import exists as exists
 from typing import Any, AnyStr, Callable, List, Optional, Sequence, Text, Tuple, TypeVar, overload
 
-from _typeshed import AnyPath, BytesPath, StrPath
-
 _T = TypeVar("_T")
 
 if sys.version_info >= (3, 6):

stdlib/2/os2emxpath.pyi

@@ -1,11 +1,10 @@
 # NB: path.pyi and stdlib/2 and stdlib/3 must remain consistent!
 import os
 import sys
+from _typeshed import AnyPath, BytesPath, StrPath
 from genericpath import exists as exists
 from typing import Any, AnyStr, Callable, List, Optional, Sequence, Text, Tuple, TypeVar, overload
 
-from _typeshed import AnyPath, BytesPath, StrPath
-
 _T = TypeVar("_T")
 
 if sys.version_info >= (3, 6):