Clarify use of resolvers in code

doc/development/api_graphql_styleguide.md

@@ -940,7 +940,9 @@ class PostResolver < BaseResolver
 end
 ```
 
-You should never re-use resolvers directly. Resolvers have a complex life-cycle, with
+While you can use the same resolver class in two different places,
+such as in two different fields where the same object is exposed, 
+you should never re-use resolver objects directly. Resolvers have a complex life-cycle, with
 authorization, readiness and resolution orchestrated by the framework, and at
 each stage [lazy values](#laziness) can be returned to take advantage of batching
 opportunities. Never instantiate a resolver or a mutation in application code.