Update instructions for VS code extension

[natke]

As it stands, creating a new Q# project fails if you install the VS code extension, using these instructions: https://docs.microsoft.com/en-us/quantum/quickstart?tabs=tabid-vscode&view=qsharp-preview

The templates need to be installed as a separate step:

From within VS you can create a new project with the standard GUI option (right click solution, new project etc). If you want to create a project from the command line you have to install the project templates, which are a separate nuget package: https://www.nuget.org/packages/Microsoft.Quantum.ProjectTemplates/0.9.1908.2906

[cgranade]

Thanks for filing this, I agree we should be more clear about the requirement that project templates are installed before hand. From the command line (whether standalone or the integrated terminal within VS Code), dotnet new -i Microsoft.Quantum.ProjectTemplates should do it. For VS Code in particular, the "Q#: Install project templates..." command from the Command Palette can also be used.

[natke]

This is fixed by #533