Fix root being inside of DSL in mutations-and-input-types.mdx

The example shows graphql implementation, where the "root" is by mistake put as string as part of the schema definition instead being a native js const

Author: alesculek

website/pages/docs/mutations-and-input-types.mdx

@@ -230,6 +230,21 @@ type Query {
 	getMessages: [Message]
 }
 
+type Mutation {
+  createMessage(input: MessageInput): Message
+  updateMessage(id: ID!, input: MessageInput): Message
+}
+`);
+
+// If Message had any complex fields, we'd put them on this object.
+class Message {
+  constructor(id, { content, author }) {
+    this.id = id;
+    this.content = content;
+    this.author = author;
+  }
+}
+
 const root = {
 	getMessage: ({ id }) => {
 		return fakeDatabase[id]
@@ -250,21 +265,6 @@ const root = {
 	}
 }
 
-type Mutation {
-  createMessage(input: MessageInput): Message
-  updateMessage(id: ID!, input: MessageInput): Message
-}
-`);
-
-// If Message had any complex fields, we'd put them on this object.
-class Message {
-  constructor(id, { content, author }) {
-    this.id = id;
-    this.content = content;
-    this.author = author;
-  }
-}
-
 const app = express();
 app.all(
   '/graphql',