Expanded demo tests to cover more public methods and functions from go/types and go/token packages, as discovered via `go doc`.
**go/types additions:**
- Type comparison functions: Identical, AssignableTo, Comparable, ConvertibleTo
- Interface checking: Implements, AssertableTo
- String formatting: TypeString, ObjectString with qualifiers
- Lookup utilities: LookupFieldOrMethod, NewMethodSet
- Type utilities: IsInterface, Default, Id
**go/token additions:**
- Utility functions: IsExported, IsIdentifier, IsKeyword, Lookup
These additions provide better coverage of the packages' public APIs and demonstrate proper usage patterns for interface conversions and method calls.
Generated with [codeagent](https://github.com/qbox/codeagent)
Co-authored-by: luoliwoshang <51194195+luoliwoshang@users.noreply.github.com>
- Removed header/footer print statements from main()
- Added '\n' prefix to section headers (except first) for consistent spacing
- Follows the pattern established in maphash and other demo files
This makes the output cleaner and consistent with other demo files in the project.
Generated with [codeagent](https://github.com/qbox/codeagent)
Co-authored-by: luoliwoshang <51194195+luoliwoshang@users.noreply.github.com>