STORM-1883: add alert when a secondary dictionary is imported

indra/newview/llfloaterspellchecksettings.cpp

@@ -310,6 +310,10 @@ void LLFloaterSpellCheckerImport::onBtnOK()
 		}
 		else
 		{
+			LLSD args = LLSD::emptyMap();
+			args["DIC_NAME"] = dict_dic;
+			LLNotificationsUtil::add("SpellingDictIsSecondary", args);
+
 			imported = true;
 		}
 	}

indra/newview/skins/default/xui/en/notifications.xml

@@ -2396,6 +2396,17 @@ Would you be my friend?
     <tag>fail</tag>
   </notification>
 
+  <notification
+   icon="alertmodal.tga"
+   name="SpellingDictIsSecondary"
+   type="alertmodal">
+The dictionary [DIC_NAME] does not appear to have an "aff" file; this means that it is a "secondary" dictionary.
+It can be used as an additional dictionary, but not as your Main dictionary.
+
+See https://wiki.secondlife.com/wiki/Adding_Spelling_Dictionaries
+    <tag>confirm</tag>
+  </notification>
+
   <notification
    icon="alertmodal.tga"
    name="SpellingDictImportFailed"