fix: improve error message (#921)

* fix: improve error message

* Improve error message in funny-buses-invite

Enhance the error message for better clarity.

Author: vonovak

.changeset/funny-buses-invite.md

@@ -0,0 +1,5 @@
+---
+"@react-native-documents/viewer": patch
+---
+
+fix: improve error message

packages/document-viewer/ios/RNDocumentViewer.mm

@@ -69,7 +69,6 @@ - (void)presentPreview:(NSString *)title
                resolve:(RCTPromiseResolveBlock)resolve
                 reject:(RCTPromiseRejectBlock)reject {
   RNDPreviewItem *item = [[RNDPreviewItem alloc] initWithURL:restoredURL title:title];
-  
   dispatch_async(dispatch_get_main_queue(), ^{
     QLPreviewController *controller = [[RNDPreviewController alloc] initWithPreviewItem:item];
     controller.modalPresentationStyle = presentationStyle;
@@ -85,7 +84,7 @@ - (void)presentPreview:(NSString *)title
       }
     } else {
       [self.presentedUrl stopAccessingSecurityScopedResource];
-      reject(RNDocViewerErrorUnableToOpenFileType, @"unsupported file", nil);
+      reject(RNDocViewerErrorUnableToOpenFileType, @"QLPreviewController cannot preview this file. It may not be supported, or deleted.", nil);
     }
   });
 }