Clarify difference between `container.name` and `k8s.container.name` (#1980)

Add more details to container name attributes to clarify the difference.

Co-authored-by: Bogdan Drutu <bogdandrutu@gmail.com>

semantic_conventions/resource/container.yaml

@@ -7,7 +7,7 @@ groups:
       - id: name
         type: string
         brief: >
-          Container name.
+          Container name used by container runtime.
         examples: ['opentelemetry-autoconf']
       - id: id
         type: string

semantic_conventions/resource/k8s.yaml

@@ -61,7 +61,9 @@ groups:
       - id: name
         type: string
         brief: >
-          The name of the Container in a Pod template.
+          The name of the Container from Pod specification, must be unique
+          within a Pod. Container runtime usually uses different globally unique
+          name (`container.name`).
         examples: ['redis']
       - id: restart_count
         type: int

specification/resource/semantic_conventions/container.md

@@ -9,7 +9,7 @@
 <!-- semconv container -->
 | Attribute  | Type | Description  | Examples  | Required |
 |---|---|---|---|---|
-| `container.name` | string | Container name. | `opentelemetry-autoconf` | No |
+| `container.name` | string | Container name used by container runtime. | `opentelemetry-autoconf` | No |
 | `container.id` | string | Container ID. Usually a UUID, as for example used to [identify Docker containers](https://docs.docker.com/engine/reference/run/#container-identification). The UUID might be abbreviated. | `a3bf90e006b2` | No |
 | `container.runtime` | string | The container runtime managing this container. | `docker`; `containerd`; `rkt` | No |
 | `container.image.name` | string | Name of the image the container was built on. | `gcr.io/opentelemetry/operator` | No |

specification/resource/semantic_conventions/k8s.md

@@ -87,7 +87,7 @@ to a running container.
 <!-- semconv k8s.container -->
 | Attribute  | Type | Description  | Examples  | Required |
 |---|---|---|---|---|
-| `k8s.container.name` | string | The name of the Container in a Pod template. | `redis` | No |
+| `k8s.container.name` | string | The name of the Container from Pod specification, must be unique within a Pod. Container runtime usually uses different globally unique name (`container.name`). | `redis` | No |
 | `k8s.container.restart_count` | int | Number of times the container was restarted. This attribute can be used to identify a particular container (running or stopped) within a container spec. | `0`; `2` | No |
 <!-- endsemconv -->