support alternate language servers in python.languageServer

[DetachHead]

currently there are only 3 options in python.LanguageServer: "Pylance", "Jedi" and "None". this isn't ideal for a couple of reasons:

• if anyone wants to use an extension that provides an alternative language server, they have to set this setting to "None" to avoid conflicting with one of those two built in language servers, which is confusing to the user. they would expect their language server to just show up as an option in that list.
• i want to be able to support jupyter notebooks in my language server, but i can't because there doesn't seem to be a way to do so without changing this hardcoded extension ID to my own extension ID and tricking it into thinking it's interfacing with pylance by implementing a PylanceApi in my extension. this would be fine, if it weren't for the fact that i'd have to fork vscode-python just to change one hardcoded constant. ideally my users of my language server shouldn't have to install two different extensions.

perhaps there could be a CustomLanguageServerApi interface similar to PylanceApi that extensions can implement and register as an option in python.languageServer.

[github-actions]

Thanks for the feature request! We are going to give the community 60 days from when this issue was created to provide 7 👍 upvotes on the opening comment to gauge general interest in this idea. If there's enough upvotes then we will consider this feature request in our future planning. If there's unfortunately not enough upvotes then we will close this issue.

[DetachHead]

after looking at how ruff supports jupyter notebooks, i think it's possible without this functionality, so i'll close this issue.