Remove word data from response payload descriptions

In older versions of MDS data was nested under a `data`
key in provider API responses, so trips data would e.g.
be response['data']['trips']. This ended up reflected
in the docs where each section would have a label like
"`data` Payload" describing what was under the `data`
key in the payload.

In MDS 2.0 this nesting was removed, `trips` is now a top
level key in the response from provider trips endpoint.
However, the docs were not updated to remove the word
"data" from the payload descriptions, leading to potential
confusion for readers of the documentation. This PR
changes "`data` Payload" to "Payload" throughout the provider
README to bring it in line with the spec.

Author: jiffyclub

provider/README.md

@@ -189,7 +189,7 @@ The `/vehicles` endpoint returns the specified vehicle (if a device_id is provid
 **Method:** `GET`  
 **[Beta feature][beta]:** No (as of 1.2.0)  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.   
-**`data` Payload:** `{ "vehicles": [] }`, an array of [Vehicle][vehicles] objects
+**Payload:** `{ "vehicles": [] }`, an array of [Vehicle][vehicles] objects
 
 _Path Parameters:_
 
@@ -234,7 +234,7 @@ The `/vehicles/status` endpoint returns the specified vehicle (if a device_id is
 **Method:** `GET`  
 **[Beta feature][beta]:** No (as of 1.2.0)  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.  
-**`data` Payload:** `{ "vehicles_status": [] }`, an array of [Vehicle Status][vehicle-status] objects
+**Payload:** `{ "vehicles_status": [] }`, an array of [Vehicle Status][vehicle-status] objects
 
 _Path Parameters:_
 
@@ -283,7 +283,7 @@ Unless stated otherwise by the municipality, the trips endpoint must return all
 **Method:** `GET`  
 **[Beta feature][beta]:** No  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.   
-**`data` Payload:** `{ "trips": [] }`, an array of [Trip][trips] objects
+**Payload:** `{ "trips": [] }`, an array of [Trip][trips] objects
 
 ### Trips - Query Parameters
 
@@ -348,7 +348,7 @@ Telemetry for a [trip](#trip) must include at least 2 points: the start point an
 **Endpoint:** `/telemetry`  
 **Method:** `GET`  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.  
-**`data` Payload:** `{ "telemetry": [] }`, an array of [Vehicle Telemetry][vehicle-telemetry] objects
+**Payload:** `{ "telemetry": [] }`, an array of [Vehicle Telemetry][vehicle-telemetry] objects
 
 [Top][toc]
 
@@ -385,7 +385,7 @@ Unless stated otherwise by the municipality, this endpoint must return only thos
 **Method:** `GET`  
 **[Beta feature][beta]:** No  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.  
-**`data` Payload:** `{ "events": [] }`, an array of [Events](/data-types.md#events) object
+**Payload:** `{ "events": [] }`, an array of [Events](/data-types.md#events) object
 
 [Top][toc]
 
@@ -447,7 +447,7 @@ See also [Stop-based Geographic Data][stop-based-geo].
 **Method:** `GET`  
 **[Beta feature][beta]:** No (as of 1.0.0)  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.  
-**`data` Payload:** `{ "events": [] }`, an array of [Events](/data-types.md#events) object objects
+**Payload:** `{ "events": [] }`, an array of [Events](/data-types.md#events) object objects
 
 #### Recent Events - Query Parameters
 
@@ -494,7 +494,7 @@ In addition to the standard [Provider payload wrapper](#response-format), respon
 **Method:** `GET`  
 **[Beta feature][beta]:** Yes (as of 1.0.0). [Leave feedback](https://github.com/openmobilityfoundation/mobility-data-specification/issues/638)  
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.    
-**`data` Payload:** `{ "stops": [] }`, an array of [Stops][stops]
+**Payload:** `{ "stops": [] }`, an array of [Stops][stops]
 
 In the case that a `stop_id` path parameter is specified, the `stops` array returned will only have one entry. In the case that no `stop_id` query parameter is specified, all stops will be returned.
 
@@ -527,8 +527,8 @@ The authenticated reports are monthly, historic flat files that may be pre-gener
 **[Beta feature][beta]:** No (as of 2.0.0). [Leave feedback](https://github.com/openmobilityfoundation/mobility-data-specification/issues/672)  
 **Usage note:** This endpoint uses media-type `text/vnd.mds+csv` instead of `application/vnd.mds+json`, see [Versioning][versioning].
 **Schema:** See [`mds-openapi`](https://github.com/openmobilityfoundation/mds-openapi) repository for schema.  
-**`data` Filename:** monthly file named by year and month, e.g. `/reports/YYYY-MM.csv`  
-**`data` Payload:** monthly CSV files of [Report](/data-types.md#Reports) objects 
+**Filename:** monthly file named by year and month, e.g. `/reports/YYYY-MM.csv`  
+**Payload:** monthly CSV files of [Report](/data-types.md#Reports) objects 
 
 #### Responses