magento/graphql-ce#741: Add extension point to set custom parameters …

…to Query Context object

- added extended docs

app/code/Magento/GraphQl/Model/Query/ContextParametersProcessorInterface.php

@@ -10,7 +10,7 @@
 /**
  * Adding custom parameters to context object:
  *
- * - Add new contextParametersProcessors item to ContextFactory in the di.xml.
+ * - Add new processors argument item to ContextFactory in the di.xml.
  * - Class must extend ContextParametersProcessorInterface.
  * - Implement execute method which adds additional data to the context though extension attributes.
  * - This data will be present in each resolver.