Clarify declarative config component provider type parameter (#4799)

From feedback here:
#4568 (comment)

/cc @open-telemetry/configuration-maintainers, @pellared

Author: jack-berg

CHANGELOG.md

@@ -44,6 +44,8 @@ release.
 - Declarative configuration: add links between SDK extension plugins and
   corresponding declarative config types.
   ([#4802](https://github.com/open-telemetry/opentelemetry-specification/pull/4802))
+- Declarative configuration: clarify Registry ComponentProvider `type` parameter
+  ([#4799](https://github.com/open-telemetry/opentelemetry-specification/pull/4799))
 
 ### Common
 

specification/configuration/sdk.md

@@ -339,15 +339,19 @@ as `ComponentProvider`s.
 **Parameters:**
 
 * `component_provider` - The `ComponentProvider`.
-* `type` - The type of plugin interface it provides (e.g. SpanExporter, Sampler,
-  etc).
+* `type` - The type of plugin interface it provides.
 * `name` - The name used to identify the type of component. This is used
   in [configuration model](./data-model.md) to specify that the
   corresponding `component_provider` is to provide the component.
 
 The `type` and `name` comprise a unique key. Register MUST return an error if it
 is called multiple times with the same `type` and `name` combination.
 
+SDKs SHOULD represent `type` in a manner that is idiomatic for their language.
+For example, a class literal, an enumeration, or similar.
+See [supported SDK extension plugins](#sdk-extension-components) for the set of
+supported `type` values.
+
 ### Examples
 
 #### Via configuration API