Update Java and Grade Versions, Fix Deprecation Warnings , Improve XML Demo , FIX #51,53 ,59.

[Hasnatrasool163]

This PR includes several important updates and improvements: Java Version Upgraded: Updated to Java 22. Gradle Version Upgraded: Updated to Gradle 8.10. Deprecated Methods: All warnings related to deprecated methods have been addressed. AutoCompletion TriggerKey support. XML Demo Fix: Resolved a minor issue with the XML demo text file, which previously threw a NullPointerException. The file name has been updated accordingly. Tree View Refresh Enhancement: Added a refresh timer to improve the responsiveness of the tree view for supported languages. Library Updates: RSyntaxTextArea updated to version 3.5.1. Autocomplete library updated to version 3.3.1. Testing: All 4 tests have passed successfully.