Fixes #1252 fix alt text setting description toggle (#1261)

* make toggle border width slightly larger

* change copy

src/view/com/util/forms/ToggleButton.tsx

···
     width: 42,
     height: 26,
     borderRadius: 15,
-    padding: 4,
-    borderWidth: 1,
+    padding: 3,
+    borderWidth: 2,
   },
   circleFill: {
     width: 16,

src/view/screens/Settings.tsx

···
           <View style={[pal.view, styles.toggleCard]}>
             <ToggleButton
               type="default-light"
-              label="Require alt text on images"
+              label="Require alt text before posting"
               labelType="lg"
               isSelected={store.preferences.requireAltTextEnabled}
               onPress={store.preferences.toggleRequireAltTextEnabled}