fix EventType bases

`StrEnum` does not exist in 3.8, so use original `(str, enum.Enum)` bases.

Lib/tkinter/__init__.py

@@ -146,10 +146,10 @@ def _splitdict(tk, v, cut_minus=True, conv=None):
 
 class EventType(str, enum.Enum):
     KeyPress = '2'
-    Key = KeyPress,
+    Key = KeyPress
     KeyRelease = '3'
     ButtonPress = '4'
-    Button = ButtonPress,
+    Button = ButtonPress
     ButtonRelease = '5'
     Motion = '6'
     Enter = '7'
@@ -180,10 +180,10 @@ class EventType(str, enum.Enum):
     Colormap = '32'
     ClientMessage = '33'    # undocumented
     Mapping = '34'          # undocumented
-    VirtualEvent = '35',    # undocumented
-    Activate = '36',
-    Deactivate = '37',
-    MouseWheel = '38',
+    VirtualEvent = '35'     # undocumented
+    Activate = '36'
+    Deactivate = '37'
+    MouseWheel = '38'
 
     def __str__(self):
         return self.name

Misc/NEWS.d/next/Library/2020-09-22-00-23-30.bpo-41817.bnh-VG.rst

@@ -0,0 +1 @@
+fix `tkinter.EventType` Enum so all members are strings, and none are tuples