This commit uses the new virtual terminal processing feature in Windows 10
to enable the use of ANSI escape codes to color ripgrep's output. This
technique is preferred over the console APIs because it seems like where
the future is heading, but also because it avoids needing to use an
intermediate buffer to deal with the Windows console in a multithreaded
environment.
This commit adds a new method to the Console type which permits toggling
the VIRTUAL_TERMINAL_PROCESSING mode on a console. Specifically, this
enables the use of ANSI escape sequences for color in Windows terminals.
The primary motivation for this commit was rust-lang/cargo#4189 where dropping a
`wincolor::Console` would call `CloseHandle` to close the console handle. Cargo
creates a few `Console` instances so it ended up closing stdout a little
earlier as intended!
The `GetStdHandle` function returns handles I believe aren't intended to be
closed (as there's no refcounting). I believe libstd doesn't close these
handles.
This commit also moves to calling `GetStdHandle` on demand which libstd changed
to doing so recently as well, preventing caching of stale handles that change
over time with calls to `SetStdHandle`.
