feat: update asset-tokenization.md (#42)

update solidity code

<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

- **New Features**
- Restructured `AssetTokenization` contract with new functions for batch
minting, burning, and setting URIs.
- Added `initialize`, `mintBatch`, `burnBatch`, `setURI` functions to
enhance contract functionality.
- Updated `Asset` struct and `AssetTransferEvent` event for efficient
asset transfers.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: bl0up