Add missing exitmsg argument to code.interact() (#2024)

According to https://docs.python.org/3/library/code.html#code.interact,
this was added in Python 3.6.

stdlib/2and3/code.pyi

@@ -1,5 +1,6 @@
 # Stubs for code
 
+import sys
 from typing import Any, Callable, Mapping, Optional
 from types import CodeType
 
@@ -15,13 +16,23 @@ class InteractiveInterpreter:
 class InteractiveConsole(InteractiveInterpreter):
     def __init__(self, locals: Optional[Mapping[str, Any]] = ...,
                  filename: str = ...) -> None: ...
-    def interact(self, banner: Optional[str] = ...) -> None: ...
+    if sys.version_info >= (3, 6):
+        def interact(self, banner: Optional[str] = ...,
+                     exitmsg: Optional[str] = ...) -> None: ...
+    else:
+        def interact(self, banner: Optional[str] = ...) -> None: ...
     def push(self, line: str) -> bool: ...
     def resetbuffer(self) -> None: ...
     def raw_input(self, prompt: str = ...) -> str: ...
 
-def interact(banner: Optional[str] = ...,
-             readfunc: Optional[Callable[[str], str]] = ...,
-             local: Optional[Mapping[str, Any]] = ...) -> None: ...
+if sys.version_info >= (3, 6):
+    def interact(banner: Optional[str] = ...,
+                 readfunc: Optional[Callable[[str], str]] = ...,
+                 local: Optional[Mapping[str, Any]] = ...,
+                 exitmsg: Optional[str] = ...) -> None: ...
+else:
+    def interact(banner: Optional[str] = ...,
+                 readfunc: Optional[Callable[[str], str]] = ...,
+                 local: Optional[Mapping[str, Any]] = ...) -> None: ...
 def compile_command(source: str, filename: str = ...,
                     symbol: str = ...) -> Optional[CodeType]: ...