Add better Windows debugging docs on how to get console output

[derekbruening]

While working on #7024 I re-realized how painful it is to get info from DR on Windows: on graphical apps there's no console output, and #7025 resulted in no popups: so no output at all!

The action item is to document that users should try running a console app (e.g., msg) to get console output or try redirecting to a file (being sure to include stderr). -log_to_stderr can also be used to get logging right there.