Fix minor typo in relay guide docs (#3586)

docs/guides/relay.mdx

@@ -194,7 +194,7 @@ The connection resolver for `relay.ListConnection` should return one of those:
 As demonstrated above, the `Node` field can be used to retrieve/refetch any
 object in the schema that implements the `Node` interface.
 
-It can be defined in in the `Query` objects in 4 ways:
+It can be defined in the `Query` objects in 4 ways:
 
 - `node: Node`: This will define a field that accepts a `GlobalID!` and returns
   a `Node` instance. This is the most basic way to define it.