Merge pull request #2857 from graphql-java/fix-selection-set-typo

Fix typo in field selection doco example

src/test/groovy/readme/FieldSelectionExamples.java

@@ -17,7 +17,7 @@ public Object get(DataFetchingEnvironment env) {
                 String userId = env.getArgument("userId");
 
                 DataFetchingFieldSelectionSet selectionSet = env.getSelectionSet();
-                if (selectionSet.contains("user/*")) {
+                if (selectionSet.contains("friends/*")) {
                     return getUserAndTheirFriends(userId);
                 } else {
                     return getUser(userId);