Refer to fully qualified class names in PHPDoc

[TysonAndre]

Because this class is in namespace Braintree;, the old PHPDoc is referring to \Braintree\Braintree_Result_Successful, which doesn't exist. (\Braintree_Result_Successful does)

This would cause minor issues with IDE suggestions and static analyzers.

An alternate acceptable fix would be to change this to \Braintree_Result_Successful, but that isn't used elsewhere

These class references were defined by class_alias:

lib/Braintree/Result/Successful.php
92:class_alias('Braintree\Result\Successful', 'Braintree_Result_Successful');

lib/Braintree/Result/Error.php
123:class_alias('Braintree\Result\Error', 'Braintree_Result_Error');

Summary

Fix nit on phpdoc, no impact is expected

Checklist

• [ ] Added changelog entry
• [ ] Ran unit tests (Check the README for instructions)

[jackellenberger]

Thanks for putting this in, @TysonAndre! We're planning on tagging the next release with this change and a few others within the next couple weeks.