fix(processors): PostProcessor -> Postprocessor (#30)

Either the typo is in the docs or in the method

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docs/processors/confirmation.md

@@ -38,7 +38,7 @@ You then need to register the postprocessor to the command manager:
 
 ```java
 commandManager.registerCommandPostProcessor(
-  confirmationManager.createPostProcessor()
+  confirmationManager.createPostprocessor()
 );
 ```