No intellisense for files untitled docs (not saved to disc)

[DonJayamanne]

Original issue microsoft/vscode-python#3498

[MikhailArkhipov]

This is b/c file without extension '.py' is not considered to be Python in the LS and hence is not loaded. I don't think it is worth fixing as workaround is trivial.

[DonJayamanne]

Discussed with @qubitron, this is required.
However, i'll let you prioritize this issue.

Use case:

• I think this is an important feature, specially for data scientists or someone starting to code, e.g. sending code to a terminal (or jupyter).
• I.e. important for experimenting, and users do that a lot with Python.

[MikhailArkhipov]

Folding into #597