Add tag for "I double-clicked my Python file and it closed itself!"

[shenanigansd]

Create a tag that explains how double-clicking a Python (.py) file spawns an instance of the user's shell that terminates when the process finishes.
It should explain to the user how to open the shell, cd to their directory (or right-click and "open PowerShell here"), and use python (or py) to run their file and see the results.

[wookie184]

Some discussion on #224, giving a tentative approval