win32: also ENABLE_VIRTUAL_TERMINAL_PROCESSING on stderr

Follow-up on jarun#277.

As discussed here[1], it's not really necessary when stdout and stderr are the
same console, but it doesn't hurt either.

Note that we did not test sys.stderr.isatty() in the code. This has been
considered, and deemed not a problem, since stdout is handled first (what
really matters) and we have a catch-all pass for any possible exception.

[1] jarun#277 (comment)

googler

@@ -3247,17 +3247,19 @@ def main():
             # https://docs.microsoft.com/en-us/windows/console/setconsolemode
             if platform.release() == '10':
                 STD_OUTPUT_HANDLE = -11
+                STD_ERROR_HANDLE = -12
                 ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004
                 try:
                     from ctypes import windll, wintypes, byref
                     kernel32 = windll.kernel32
-                    stdout_handle = kernel32.GetStdHandle(STD_OUTPUT_HANDLE)
-                    old_mode = wintypes.DWORD()
-                    if not kernel32.GetConsoleMode(stdout_handle, byref(old_mode)):
-                        raise RuntimeError('GetConsoleMode failed')
-                    new_mode = old_mode.value | ENABLE_VIRTUAL_TERMINAL_PROCESSING
-                    if not kernel32.SetConsoleMode(stdout_handle, new_mode):
-                        raise RuntimeError('SetConsoleMode failed')
+                    for nhandle in (STD_OUTPUT_HANDLE, STD_ERROR_HANDLE):
+                        handle = kernel32.GetStdHandle(nhandle)
+                        old_mode = wintypes.DWORD()
+                        if not kernel32.GetConsoleMode(handle, byref(old_mode)):
+                            raise RuntimeError('GetConsoleMode failed')
+                        new_mode = old_mode.value | ENABLE_VIRTUAL_TERMINAL_PROCESSING
+                        if not kernel32.SetConsoleMode(handle, new_mode):
+                            raise RuntimeError('SetConsoleMode failed')
                     # Note: No need to restore at exit. SetConsoleMode seems to
                     # be limited to the calling process.
                 except Exception: