Be more specific when toasting "Success!"

Closes #4871
//FREEBIE

res/values/strings.xml

@@ -169,7 +169,7 @@
         <item quantity="one">Error while saving attachment to storage!</item>
         <item quantity="other">Error while saving attachments to storage!</item>
     </plurals>
-    <string name="ConversationFragment_success_exclamation">Success!</string>
+    <string name="ConversationFragment_file_saved_successfully">File saved successfully.</string>
     <string name="ConversationFragment_unable_to_write_to_sd_card_exclamation">Unable to write to storage!</string>
     <plurals name="ConversationFragment_saving_n_attachments">
         <item quantity="one">Saving attachment</item>
@@ -259,7 +259,7 @@
     <string name="ExportFragment_exporting_plaintext_to_storage">Exporting plaintext to storage...</string>
     <string name="ExportFragment_error_unable_to_write_to_storage">Error, unable to write to storage.</string>
     <string name="ExportFragment_error_while_writing_to_storage">Error while writing to storage.</string>
-    <string name="ExportFragment_success">Success!</string>
+    <string name="ExportFragment_export_successful">Export successful.</string>
 
     <!-- GcmRefreshJob -->
     <string name="GcmRefreshJob_Permanent_Signal_communication_failure">Permanent Signal communication failure!</string>

src/org/thoughtcrime/securesms/ExportFragment.java

@@ -134,7 +134,7 @@ public class ExportFragment extends Fragment {
           break;
         case SUCCESS:
           Toast.makeText(context,
-                         context.getString(R.string.ExportFragment_success),
+                         context.getString(R.string.ExportFragment_export_successful),
                          Toast.LENGTH_LONG).show();
           break;
       }

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

@@ -111,7 +111,7 @@ public class SaveAttachmentTask extends ProgressDialogAsyncTask<SaveAttachmentTa
                        Toast.LENGTH_LONG).show();
         break;
       case SUCCESS:
-        Toast.makeText(context, R.string.ConversationFragment_success_exclamation,
+        Toast.makeText(context, R.string.ConversationFragment_file_saved_successfully,
             Toast.LENGTH_LONG).show();
         break;
       case WRITE_ACCESS_FAILURE: