refund doc correction

[ankitdas13]

Doc reference : https://razorpay.com/docs/api/refunds

[sofiya02]

1. Create a normal refund - response "speed_requested": "normal" missing
2. Create an instant refund - 'speed_processed': 'normal' missing
   Check above both api in post as with speed and receipt parameter its throwing error

[ankitdas13]

1. Create a normal refund - response "speed_requested": "normal" missing
2. Create an instant refund - 'speed_processed': 'normal' missing
   Check above both api in post as with speed and receipt parameter its throwing error

@sofiya02 i have updated the response parameter and put receipt parameters unique while call this two api's

[sofiya02]

create a normal refund and instant refund please correct receipt no 132

[ankitdas13]

create a normal refund and instant refund please correct receipt no 132

Added

[sofiya02]

LGTM