Include settings sync feature in Web IDE doc

Issue: Document Web IDE Settings Sync functionalities (#443510 - closed)

What does this MR do and why?

This MR provides a feature summary of Settings Sync in the Web IDE documentation to communicate which IDE settings are supported.

Screenshot

How to validate locally

• Settings Sync is enabled automatically in the Web IDE.
• To configure settings, go to the Command Palette in the Web IDE and enter Settings Sync: Configure in the search bar
• To view synced data, go to the Command Palette in the Web IDE and enter Settings Sync: Show Synced Data in the search bar