global, single non-letter key hotkeys e.g `.` or `,` don't work on Windows

[wis]

  HotKey(
    KeyCode.comma,
    modifiers: [],
    scope: HotKeyScope.system,
  )

I think the issue is because these characters are not assign to any VK_ key values here:

hotkey_manager/windows/hotkey_manager_plugin.cpp

Lines 81 to 83 in a9d9120

	std::make_pair("comma", 0),
	std::make_pair("period", 0),
	std::make_pair("slash", 0),

[lijy91]

I made some changes to keymap, see #32 (comment)