Import l10n. (#2899)

Author: mozilla-l10n-automation-bot

app/src/main/res/values-es-rES/strings.xml

@@ -141,6 +141,10 @@
          opens a dialog box that contains language-related settings. -->
     <string name="settings_language">Idioma</string>
 
+    <!-- This string is used to label the first string in the language list for voice and display languages.
+         If chosen the device will use the system language as the main language. -->
+    <string name="settings_language_follow_device">Usar el idioma del dispositivo</string>
+
     <!-- This string is used to label a text label for selecting the language in the 'Language' dialog window
          (accessible from the browser's Settings' dialog window). Below this string appears
          the different options for language settings. -->