mention that allowing 2G may be necessary for calls to work

Signed-off-by: r3g_5z <june@girlboss.ceo>

static/usage.html

@@ -1257,7 +1257,8 @@
                     <li>Follow your carrier's instructions for setting up APNs, this can be found in
                         Settings ➔ Network &amp; Internet ➔ SIMs ➔ Access Point Names</li>
                     <li>If calls do not work and you have <a href="#lte-only-mode">LTE-only mode</a> enabled,
-                        try toggling it off. Your carrier may not properly support VoLTE.</li>
+                        try toggling it off. If "Allow 2G" is disabled, try toggling it back on. Your carrier
+                        may not properly support VoLTE.</li>
                     <li>As a last resort you may need to ask your carrier for a replacement SIM card.</li>
                 </ul>