[Documentation] `ComponentMetricId` is not documented

[matthias-wende-frequenz]

What happened?

The ComponentMetricId is used as a type for parameters in several places in the Documentation but the Type itself is not documented, which makes it hard to determine what to pass.

What did you expect instead?

Link to the documentation or definition.

Affected version(s)

No response

Affected part(s)

Documentation (part:docs)

Extra information

This is the link to the definition.
https://github.com/frequenz-floss/frequenz-client-microgrid-python/blob/v0.x.x/src/frequenz/client/microgrid/_component.py#L192

[llucax]

So the class is documented, it is just not publicly exposed, right? So this issue is only about re-exporting it in https://github.com/frequenz-floss/frequenz-client-microgrid-python/blob/v0.x.x/src/frequenz/client/microgrid/__init__.py, right? Or do you think the class documentation needs to be improved too?

[matthias-wende-frequenz]

It's about exposing it publicly.

[llucax]

Easy fix then.