react-native-code-gen Add Enum Type support for C++ TurboModules

Summary:
There are cases where we want to pass an enum type into a TurboModule method which is handy to restrict certain arguments to a restricted set of values, e.g. restricting quality to ```enum Quality { SD, HD, }```

Approach:
- We are not generating an ```enum``` type in C++ but rather just cast type safe to the corresponding member type.

- We don't support mixed enum types at this time, e.g. ```export enum StringOption { One = 'one', Two = 2, Three = 'three', };``` will not work. See: https://www.typescriptlang.org/docs/handbook/enums.html#heterogeneous-enums

- We only support untyped (default to String), String, and Number enum properties

This is for C++ only, Java and ObjC are not supported atm.

Changelog:
[General][Added] - react-native-code-gen Add Enum Type support for C++ TurboModules

Reviewed By: RSNara

Differential Revision: D38880963

fbshipit-source-id: f2399b29948306bc555429b6f96c43ea4c39c46e

packages/react-native-codegen/src/generators/modules/GenerateModuleJavaSpec.js

@@ -156,7 +156,10 @@ function translateFunctionParamToJavaType(
       imports.add('com.facebook.react.bridge.Callback');
       return 'Callback';
     default:
-      (realTypeAnnotation.type: 'MixedTypeAnnotation' | 'UnionTypeAnnotation');
+      (realTypeAnnotation.type:
+        | 'EnumDeclaration'
+        | 'MixedTypeAnnotation'
+        | 'UnionTypeAnnotation');
       throw new Error(createErrorMessage(realTypeAnnotation.type));
   }
 }
@@ -220,7 +223,10 @@ function translateFunctionReturnTypeToJavaType(
       imports.add('com.facebook.react.bridge.WritableArray');
       return wrapIntoNullableIfNeeded('WritableArray');
     default:
-      (realTypeAnnotation.type: 'MixedTypeAnnotation' | 'UnionTypeAnnotation');
+      (realTypeAnnotation.type:
+        | 'EnumDeclaration'
+        | 'MixedTypeAnnotation'
+        | 'UnionTypeAnnotation');
       throw new Error(createErrorMessage(realTypeAnnotation.type));
   }
 }
@@ -272,7 +278,10 @@ function getFalsyReturnStatementFromReturnType(
     case 'ArrayTypeAnnotation':
       return 'return null;';
     default:
-      (realTypeAnnotation.type: 'MixedTypeAnnotation' | 'UnionTypeAnnotation');
+      (realTypeAnnotation.type:
+        | 'EnumDeclaration'
+        | 'MixedTypeAnnotation'
+        | 'UnionTypeAnnotation');
       throw new Error(createErrorMessage(realTypeAnnotation.type));
   }
 }