Fix grafana describe examples (#457)

* fix grafana describe examples

* update docs

Author: GokceGK

docs/stackit_observability_grafana_describe.md

@@ -16,13 +16,13 @@ stackit observability grafana describe INSTANCE_ID [flags]
 
 ```
   Get details of the Grafana configuration of an Observability instance with ID "xxx"
-  $ stackit observability credentials describe xxx
+  $ stackit observability grafana describe xxx
 
   Get details of the Grafana configuration of an Observability instance with ID "xxx" and show the initial admin password
-  $ stackit observability credentials describe xxx --show-password
+  $ stackit observability grafana describe xxx --show-password
 
   Get details of the Grafana configuration of an Observability instance with ID "xxx" in JSON format
-  $ stackit observability credentials describe xxx --output-format json
+  $ stackit observability grafana describe xxx --output-format json
 ```
 
 ### Options

internal/cmd/observability/grafana/describe/describe.go

@@ -44,13 +44,13 @@ func NewCmd(p *print.Printer) *cobra.Command {
 		Example: examples.Build(
 			examples.NewExample(
 				`Get details of the Grafana configuration of an Observability instance with ID "xxx"`,
-				"$ stackit observability credentials describe xxx"),
+				"$ stackit observability grafana describe xxx"),
 			examples.NewExample(
 				`Get details of the Grafana configuration of an Observability instance with ID "xxx" and show the initial admin password`,
-				"$ stackit observability credentials describe xxx --show-password"),
+				"$ stackit observability grafana describe xxx --show-password"),
 			examples.NewExample(
 				`Get details of the Grafana configuration of an Observability instance with ID "xxx" in JSON format`,
-				"$ stackit observability credentials describe xxx --output-format json"),
+				"$ stackit observability grafana describe xxx --output-format json"),
 		),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			ctx := context.Background()