docs(metrics): list known metric names in --metric help text (DX-5700) (#32)

The --metric flag help was uneven: 'qn endpoint metrics' showed only two
example names, and 'qn metrics account' / 'qn metrics endpoint' gave no
examples at all. List the known metric names (method_calls_over_time,
metered_endpoint_data_over_time, metered_endpoint_credits_over_time,
credits_over_time) on all three, keeping response_status_breakdown on
the endpoint-scoped commands. Help text only; no validation change.

223 tests pass.

Author: johnpmitsch

src/commands/endpoint/mod.rs

@@ -200,7 +200,8 @@ pub struct MetricsArgs {
     /// Endpoint id.
     #[arg(value_name = "ENDPOINT_ID")]
     pub id: String,
-    /// Metric name (e.g. `method_calls_over_time`, `response_status_breakdown`).
+    /// Metric name (e.g. `method_calls_over_time`, `metered_endpoint_data_over_time`,
+    /// `metered_endpoint_credits_over_time`, `credits_over_time`, `response_status_breakdown`).
     #[arg(long)]
     pub metric: String,
     /// Period (`hour`, `day`, `week`, `month`).

src/commands/metrics.rs

@@ -28,7 +28,8 @@ pub struct AccountArgs {
     /// Period.
     #[arg(long, value_parser = ["hour", "day", "week", "month"])]
     pub period: String,
-    /// Metric name.
+    /// Metric name (e.g. `method_calls_over_time`, `metered_endpoint_data_over_time`,
+    /// `metered_endpoint_credits_over_time`, `credits_over_time`).
     #[arg(long)]
     pub metric: String,
     /// Percentile (for latency metrics).
@@ -44,7 +45,8 @@ pub struct EndpointArgs {
     /// Period.
     #[arg(long, value_parser = ["hour", "day", "week", "month"])]
     pub period: String,
-    /// Metric name.
+    /// Metric name (e.g. `method_calls_over_time`, `metered_endpoint_data_over_time`,
+    /// `metered_endpoint_credits_over_time`, `credits_over_time`, `response_status_breakdown`).
     #[arg(long)]
     pub metric: String,
 }