fix(graphql-types-generator): correct typename for nested fragments (#262)

Author: AaronZyLee

packages/graphql-types-generator/src/typescript/codeGeneration.ts

@@ -307,7 +307,7 @@ export function interfaceDeclarationForFragment(generator: CodeGenerator, fragme
               type: { name: `"${fragment.typeCondition}"` } as GraphQLType,
             };
           } else {
-            return field;
+            return updateTypeNameField(field);
           }
         });
 

packages/graphql-types-generator/test/angular/__snapshots__/index.js.snap

@@ -1938,7 +1938,7 @@ export type humanDetailsFragment = {
   name: string;
   // A list of starships this person has piloted, or an empty list if none
   starships?: Array<{
-    __typename: string;
+    __typename: \\"Starship\\";
     // The ID of the starship
     id: string;
     // The name of the starship

packages/graphql-types-generator/test/typescript/__snapshots__/codeGeneration.js.snap

@@ -1467,7 +1467,7 @@ export type humanDetailsFragment = {
   name: string,
   // A list of starships this person has piloted, or an empty list if none
   starships?:  Array< {
-    __typename: string,
+    __typename: \\"Starship\\",
     // The ID of the starship
     id: string,
     // The name of the starship