Use assignment instead of annotation in third party enums (#11957)

stubs/antlr4-python3-runtime/antlr4/atn/ATNType.pyi

@@ -1,7 +1,7 @@
 from enum import IntEnum
 
 class ATNType(IntEnum):
-    LEXER: int
-    PARSER: int
+    LEXER = 0
+    PARSER = 1
     @classmethod
     def fromOrdinal(cls, i: int): ...

stubs/antlr4-python3-runtime/antlr4/atn/LexerAction.pyi

@@ -4,14 +4,14 @@ from enum import IntEnum
 Lexer: Incomplete
 
 class LexerActionType(IntEnum):
-    CHANNEL: int
-    CUSTOM: int
-    MODE: int
-    MORE: int
-    POP_MODE: int
-    PUSH_MODE: int
-    SKIP: int
-    TYPE: int
+    CHANNEL = 0
+    CUSTOM = 1
+    MODE = 2
+    MORE = 3
+    POP_MODE = 4
+    PUSH_MODE = 5
+    SKIP = 6
+    TYPE = 7
 
 class LexerAction:
     actionType: Incomplete

stubs/antlr4-python3-runtime/antlr4/atn/PredictionMode.pyi

@@ -8,9 +8,9 @@ from antlr4.atn.ATNState import RuleStopState as RuleStopState
 from antlr4.atn.SemanticContext import SemanticContext as SemanticContext
 
 class PredictionMode(Enum):
-    SLL: int
-    LL: int
-    LL_EXACT_AMBIG_DETECTION: int
+    SLL = 0
+    LL = 1
+    LL_EXACT_AMBIG_DETECTION = 2
     @classmethod
     def hasSLLConflictTerminatingPrediction(cls, mode: PredictionMode, configs: ATNConfigSet): ...
     @classmethod