Rename some strings

// FREEBIE

res/values/strings.xml

@@ -914,9 +914,9 @@
     <string name="preferences__default">Default</string>
     <string name="preferences__language">Language</string>
     <string name="preferences__language_summary">Language %s</string>
-    <string name="preferences__signal_messages">Signal messages</string>
+    <string name="preferences__signal">Signal</string>
     <string name="preferences__use_the_data_channel_for_communication_with_other_signal_users">
-        Free private messaging to Signal users
+        Free private messaging and calling to Signal users
     </string>
     <string name="preferences__submit_debug_log">Submit debug log</string>
     <string name="preferences__support_wifi_calling">\'WiFi Calling\' compatibility mode</string>

res/xml/preferences_advanced.xml

@@ -4,7 +4,7 @@
     <org.thoughtcrime.securesms.components.SwitchPreferenceCompat
                         android:defaultValue="false"
                         android:key="pref_toggle_push_messaging"
-                        android:title="@string/preferences__signal_messages"
+                        android:title="@string/preferences__signal"
                         android:summary="@string/preferences__use_the_data_channel_for_communication_with_other_signal_users"/>
 
     <org.thoughtcrime.securesms.components.SwitchPreferenceCompat