Update header docs for paypal custom handler
Update header docs for paypal custom handler

braintree/braintree_ios,billCTG/braintree_ios,apascual/braintree_ios,apascual/braintree_ios,braintree/braintree_ios,apascual/braintree_ios,billCTG/braintree_ios,braintree/braintree_ios,braintree/braintree_ios,billCTG/braintree_ios,billCTG/braintree_ios,billCTG/braintree_ios,apascual/braintree_ios