Fix Placeholder in NFT Error Messages

[donatik27]

Pull Request Summary

Changes Made

1. File: examples/gen-nft/src/contract.rs

   • Old Code: .expect("NFT {token_id} not found")
   • New Code: .expect("NFT not found")

2. File: examples/non-fungible/src/contract.rs

   • Old Code: .expect("NFT {token_id} not found")
   • New Code: .expect("NFT not found")

Reason for Changes

Improved clarity and consistency of error messages. The previous message included a placeholder {token_id} that was not replaced, leading to confusion. The new message "NFT not found" is clear and concise, aiding in debugging.

[afck]

Good catch!