Update migration guide

website/docs/docs/guides/migration-guide/upgrading-to-v1.1.md

@@ -22,7 +22,9 @@ There are no breaking changes for end users of dbt. We are committed to providin
 
 ### For maintainers of adapter plugins
 
-The abstractmethods `get_response` and `execute` now only return `connection.AdapterReponse` in type hints. Previously, they could return a string. We encourage you to update your methods to return an object of class `AdapterResponse`, or implement a subclass specific to your adapter. This also gives you the opportunity to add fields specific to your adapter's query execution, such as `rows_affected` or `bytes_processed`.
+We have reworked the testing suite for adapter plugin functionality. For details on the new testing suite, see: ["Testing a new adapter"](testing-a-new-adapter)
+
+The abstract methods `get_response` and `execute` now only return `connection.AdapterReponse` in type hints. Previously, they could return a string. We encourage you to update your methods to return an object of class `AdapterResponse`, or implement a subclass specific to your adapter. This also gives you the opportunity to add fields specific to your adapter's query execution, such as `rows_affected` or `bytes_processed`.
 
 ### For consumers of dbt artifacts (metadata)
 
@@ -32,6 +34,6 @@ The manifest schema version will be updated to v5. The only change is to the def
 
 _Note: If you're contributing docs for a new or updated feature in v1.1, please link those docs changes below!_
 
-### Plugins
+### Adapter Plugins
 
 - **dbt-spark** added support for a [`session` connection method](spark-profile#session), for use with a pySpark session, to support rapid iteration when developing advanced or experimental functionality. This connection method is not recommended for new users, and it is not supported in dbt Cloud.