Clarify collector exporter key format in docs (open-telemetry#5771)

Co-authored-by: opentelemetrybot <[email protected]>
Co-authored-by: Severin Neumann <[email protected]>

content/en/docs/collector/configuration.md

@@ -415,10 +415,14 @@ Exporters send data to one or more backends or destinations. Exporters can be
 pull or push based, and may support one or more
 [data sources](/docs/concepts/signals/).
 
-The `exporters` section contains exporters configuration. Most exporters require
-configuration to specify at least the destination, as well as security settings,
-like authentication tokens or TLS certificates. Any setting you specify
-overrides the default values, if present.
+Each key within the `exporters` section defines an exporter instance, The key
+follows the `type/name` format, where `type` specifies the exporter type (e.g.,
+`otlp`, `kafka`, `prometheus`), and `name` (optional) can be appended to provide
+a unique name for multiple instance of the same type.
+
+Most exporters require configuration to specify at least the destination, as
+well as security settings, like authentication tokens or TLS certificates. Any
+setting you specify overrides the default values, if present.
 
 > Configuring an exporter does not enable it. Exporters are enabled by adding
 > them to the appropriate pipelines within the [service](#service) section.