Why

Part of the ongoing improvements for docs are under the Develop section.

How

This PR updates the Assets guide by:

• Restructuring the guide to provide actionable user-facing steps for loading an asset using either the config plugin oruseAssetshook fromexpo-assetlibrary.
• Also mention these two methods in the section headings.
• Updating the examples to use TypeScript file extensions by default
• Updating verbiage.
• Adding an additional information section and moving sections on optimizing assets and fonts under it.
• Fix a broken link to the Fonts guide on adding a custom font.

Test Plan

Run docs locally and visit:http://localhost:3002/develop/user-interface/assets

Checklist

• Documentation is up to date to reflect these changes (eg:https://docs.expo.devand README.md).
• Conforms with theDocumentation Writing Style Guide
• This diff will work correctly fornpx expo prebuild& EAS Build (eg: updated a module plugin).