Remove experimental_isSourceElement from printer features
- Remove experimental_isSourceElement from estreeJsonPrinter features
- Remove feature check in isSourceElement function
- isJsonSourceElement logic is already used internally in getFormatRanges
- Simplify by keeping JSON source element check inline in range.js
- All tests passing
Co-authored-by: fisker <172584+fisker@users.noreply.github.com>
