Make toast after saving attachment translatable

Closes #7374

res/values/strings.xml

@@ -689,6 +689,7 @@
 
     <!-- SaveAttachmentTask -->
     <string name="SaveAttachmentTask_open_directory">Open directory</string>
+    <string name="SaveAttachmentTask_saved_to">Saved to %s</string>
 
     <!-- SearchToolbar -->
     <string name="SearchToolbar_search">Search</string>

src/org/thoughtcrime/securesms/util/SaveAttachmentTask.java

@@ -188,7 +188,10 @@ public class SaveAttachmentTask extends ProgressDialogAsyncTask<SaveAttachmentTa
                        Toast.LENGTH_LONG).show();
         break;
       case SUCCESS:
-        Toast.makeText(context, String.format("Saved to %s", result.second()), Toast.LENGTH_LONG).show();
+        Toast.makeText(context,
+                       context.getResources().getString(R.string.SaveAttachmentTask_saved_to,
+                                                        result.second()),
+                       Toast.LENGTH_LONG).show();
         break;
       case WRITE_ACCESS_FAILURE:
         Toast.makeText(context, R.string.ConversationFragment_unable_to_write_to_sd_card_exclamation,