Support nested repositories

[babolivier]

I'm currently working with a project that is based on top of another. The way those two code bases relate to each other is that one is supposed to be located as a subdirectory of the other. However, both are separate Mercurial repositories.

I have noticed that vscode-hg only considers the top-level repository. If I open a file located in the nested repository, the indicator on the bottom left corner of VS Code still shows information for the top-level one, and annotations don't work.

I'm aware that I could work around this issue by opening the nested repository in another instance of VS Code, but that configuration would be a bit awkward as the nested project relies quite a lot on the top-level one in terms of configuration, tooling and actual code.

Thus a feature request I would like to share for this extension would be support for nested repositories in this kind of configuration. It looks like this is already supported in VS Code for Git (microsoft/vscode#37947) so I assume this would also be of interest to folks in here.