[cicd] refine brief for vcs.change.time_to_approval metric

Author: christophe-kamphaus-jemmic

docs/cicd/cicd-metrics.md

@@ -112,7 +112,7 @@ This metric is [recommended][MetricRecommended].
 
 | Name     | Instrument Type | Unit (UCUM) | Description    | Stability |
 | -------- | --------------- | ----------- | -------------- | --------- |
-| `vcs.change.time_to_approval` | Gauge | `s` | The amount of time it took a change (pull request/merge request/changelist) to get the first approval | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
+| `vcs.change.time_to_approval` | Gauge | `s` | The amount of time since its creation it took a change (pull request/merge request/changelist) to get the first approval | ![Experimental](https://img.shields.io/badge/-experimental-blue) |
 
 | Attribute  | Type | Description  | Examples  | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability |
 |---|---|---|---|---|---|

model/vcs/metrics.yaml

@@ -28,7 +28,7 @@ groups:
   - id: metric.vcs.change.time_to_approval
     type: metric
     metric_name: vcs.change.time_to_approval
-    brief: 'The amount of time it took a change (pull request/merge request/changelist) to get the first approval'
+    brief: 'The amount of time since its creation it took a change (pull request/merge request/changelist) to get the first approval'
     instrument: gauge
     unit: "s"
     stability: experimental