Possibility to use more than one namespace in the topic-plugin

[erik-alm]

Thanks for a great plugin!

I tried this syntax that does not seem to be supported:

{{topic>ns1 ns2?tag1}}

I.e. listing tags from more than one namespace. I got the idea from the count-plugin that has support for several namespaces.

So my suggestion is to support for more than one namespace in topic as well.

(Unless this is an undocumented feature that currently has bugs? I'm on 2024-02-06a "Kaos", latest version of the plugin).

Issue #54 might be related.

Cheers!