Allow setting a scale factor on Windows

Fixes #1756

src/UserSettingsPage.cpp

@@ -1420,7 +1420,8 @@ UserSettingsModel::data(const QModelIndex &index, int role) const
             return tr("Will prevent swipe motions like swiping left/right between Rooms and "
                       "Timeline, or swiping a message to reply.");
         case ScaleFactor:
-            return tr("Change the scale factor of the whole user interface.");
+            return tr("Change the scale factor of the whole user interface. Requires a restart to "
+                      "take effect.");
         case UseStunServer:
             return tr(
               "Will use turn.matrix.org as assist when your home server does not offer one.");

src/main.cpp

@@ -169,7 +169,7 @@ main(int argc, char *argv[])
 
     // this needs to be after setting the application name. Or how would we find our settings
     // file then?
-#if defined(Q_OS_UNIX) && !defined(Q_OS_MACOS)
+#if !defined(Q_OS_MACOS)
     if (qgetenv("QT_SCALE_FACTOR").size() == 0) {
         float factor = utils::scaleFactor();