docs(account): improve module docstring for account_allowance_approve_transaction_nft example

 Updated CHANGELOG.md

Signed-off-by: Sarthak Tyagi <[email protected]>

Author: sarthak-cs

CHANGELOG.md

@@ -61,6 +61,7 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - Add Linked Issue Enforcer to automatically close PRs without linked issues `.github/workflows/bot-linked-issue-enforcer.yml`.
 
 ### Changed
+- Improved docstring for `account_allowance_approve_transaction_nft.py` with purpose, key concepts and required vs optional steps.
 - Updated Codecov coverage thresholds in 'codecov.yml' to require 90% of project coverage and 92% of patch coverage (#1157)
 - Reduce office-hours reminder spam by posting only on each user's most recent open PR, grouping by author and sorting by creation time (#1121)
 - Pylint cleanup for token_airdrop_transaction_cancel.py (#1081) [@tiya-15](https://github.com/tiya-15)

examples/account/account_allowance_approve_transaction_nft.py

@@ -1,17 +1,32 @@
 """
-This example demonstrates approving an NFT allowance and transferring the NFT using it.
-
-- Creates an owner, spender, and receiver account.
-- Creates an NFT.
-- Mints the NFT to the owner's account.
-- Associates the NFT with the receiver's account.
-- Approves the spender to spend the owner's NFT.
-- Spender (as payer) transfers the NFT from the owner to the receiver.
+Example: Approving an NFT allowance and transferring the NFT using it.
+
+Why:
+    This example demonstrates how NFT allowances work on the Hedera network.
+    It shows how an owner can approve another account (the spender) to transfer
+    their NFT to a receiver. This is useful for understanding NFT permissions
+    and automated transfers in decentralized applications.
+
+Key Concepts:
+    - Owner: The account that owns the NFT and grants allowance.
+    - Spender: The account approved to transfer the Owner's NFT.
+    - Receiver: The account that will receive the NFT.
+    - NFT Allowance: Permission given by the Owner to the Spender to transfer NFT(s).
+
+High-Level Steps:
+    Required:
+        1. Create Owner, Spender, and Receiver accounts.
+        2. Create and mint an NFT to the Owner.
+        3. Approve the Spender to transfer the Owner's NFT.
+        4. Transfer the NFT using the approved allowance.
+    Optional:
+        - Associate the NFT with the Receiver account (depends on network/account setup).
 
 Usage:
     uv run examples/account/account_allowance_approve_transaction_nft.py
 """
 
+
 import os
 import sys
 from dotenv import load_dotenv