Update metrics names in the docs (#490)

Author: mthenw

docs/prometheus-metrics.md

@@ -4,13 +4,13 @@ Both Events and Configuration API exposes Prometheus metrics. The metrics are ac
 
 ## Events API Metrics
 
-| Metric Name                       | Description                                                  | Type    | Labels           |
-| --------------------------------- | ------------------------------------------------------------ | ------- | ---------------- |
-| `gateway_events_received_total`   | Total of events received.                                    | Counter | `space`, `type` |
-| `gateway_events_processed_total`  | Total of processed events.                                   | Counter | `space`, `type`  |
-| `gateway_events_dropped_total`    | Total of events dropped due to insufficient processing power. | Counter | `space`, `type`  |
-| `gateway_events_backlog`          | Gauge of asynchronous events count waiting to be processed.  | Gauge   |                  |
-| `gateway_events_custom_processing_seconds` | Bucketed histogram of processing duration of an event. From receiving the asynchronous custom event to calling a function. | Histogram | |
+| Metric Name                           | Description                                                   | Type    | Labels           |
+| ------------------------------------- | ------------------------------------------------------------- | ------- | ---------------- |
+| `eventgateway_events_received_total`  | Total of events received.                                     | Counter | `space`, `type` |
+| `eventgateway_events_processed_total` | Total of processed events.                                    | Counter | `space`, `type`  |
+| `eventgateway_events_dropped_total`   | Total of events dropped due to insufficient processing power. | Counter | `space`, `type`  |
+| `eventgateway_events_backlog`         | Gauge of asynchronous events count waiting to be processed.   | Gauge   |                  |
+| `eventgateway_events_custom_processing_seconds` | Bucketed histogram of processing duration of an event. From receiving the asynchronous custom event to calling a function. | Histogram | |
 
 ### Labels
 
@@ -21,11 +21,11 @@ Both Events and Configuration API exposes Prometheus metrics. The metrics are ac
 
 | Metric Name                               | Description                                                  | Type      | Labels                            |
 | ----------------------------------------- | ------------------------------------------------------------ | --------- | --------------------------------- |
-| `gateway_eventtypes_total`                | Gauge of registered event types count.                       | Gauge     | `space`                           |
-| `gateway_functions_total`                 | Gauge of registered functions count.                         | Gauge     | `space`                           |
-| `gateway_subscriptions_total`             | Gauge of created subscriptions count.                        | Gauge     | `space`                           |
-| `gateway_config_requests_total`           | Total of Config API requests.                                | Counter   | `space`,  `resource`, `operation` |
-| `gateway_config_request_duration_seconds` | Bucketed histogram of request duration of Config API requests. | Histogram |                                   |
+| `eventgateway_eventtypes_total`                | Gauge of registered event types count.                       | Gauge     | `space`                           |
+| `eventgateway_functions_total`                 | Gauge of registered functions count.                         | Gauge     | `space`                           |
+| `eventgateway_subscriptions_total`             | Gauge of created subscriptions count.                        | Gauge     | `space`                           |
+| `eventgateway_config_requests_total`           | Total of Config API requests.                                | Counter   | `space`,  `resource`, `operation` |
+| `eventgateway_config_request_duration_seconds` | Bucketed histogram of request duration of Config API requests. | Histogram |                                   |
 ### Labels
 
 - `space` - space name