Adds Cohere completion example. (#4990) (#4996)

(cherry picked from commit c98011f)

Co-authored-by: István Zoltán Szabó <szabosteve@gmail.com>

Author: github-actions[bot]

specification/inference/put_cohere/examples/request/PutCohereRequestExample3.yaml

@@ -0,0 +1,12 @@
+summary: A completion task
+description: Run `PUT _inference/completion/cohere-completion` to create an inference endpoint that performs a completion task.
+method_request: 'PUT _inference/completion/cohere-completion'
+# type: "request"
+value: |-
+  {
+      "service": "cohere",
+      "service_settings": {
+          "api_key": "Cohere-API-key",
+          "model_id": "command-a-03-2025"
+      }
+  }