io/key: add NameSpace, report it on Linux

Fixes gio#204.

Signed-off-by: pierre <pierre.curto@gmail.com>

app/internal/wm/os_js.go

@@ -570,7 +570,7 @@ func translateKey(k string) (string, bool) {
 	case "Tab":
 		n = key.NameTab
 	case " ":
-		n = "Space"
+		n = key.NameSpace
 	case "F1", "F2", "F3", "F4", "F5", "F6", "F7", "F8", "F9", "F10", "F11", "F12":
 		n = k
 	default:

app/internal/wm/os_macos.go

@@ -443,7 +443,7 @@ func convertKey(k rune) (string, bool) {
 	case 0x09, 0x19:
 		n = key.NameTab
 	case 0x20:
-		n = "Space"
+		n = key.NameSpace
 	default:
 		k = unicode.ToUpper(k)
 		if !unicode.IsPrint(k) {

app/internal/wm/os_windows.go

@@ -671,7 +671,7 @@ func convertKeyCode(code uintptr) (string, bool) {
 	case windows.VK_TAB:
 		r = key.NameTab
 	case windows.VK_SPACE:
-		r = "Space"
+		r = key.NameSpace
 	case windows.VK_OEM_1:
 		r = ";"
 	case windows.VK_OEM_PLUS: