Detect opening a workspace folder with a symlink on the path and output a warning message

[sean-mcmanus]

Assuming #4573 can't be fixed soon, it seems like it should be pretty easy to detect that the workspace folder path has a symlink on it and output a warning message.

Follow up to #9035 .

[reporter123]

If we can give a warning what's stopping us from actual resolving the path so vscode and its users don't have to deal with that detail. I can only see this as an interim stop gap measure. Better than doing nothing but not really a long term solution.

[Colengms]

Closing, as #4573 has been addressed.