Prepare v0.2.0 release (#51)

- Update version numbers to 0.2.0 in both Cargo.toml files
- Add comprehensive CHANGELOG.md entry for v0.2.0 with map patterns and improvements
- Update README.md with new map pattern feature and v0.2.0 version
- Update documentation examples with map patterns and version bump
- Add wildcard map pattern documentation

Fix span propagation type errors (#43)

Type errors in comparison patterns (e.g., `field: == 123`) now point to the
specific problematic token instead of the entire macro call. This is achieved
by using quote_spanned! for all comparison operations to preserve the original
token spans through macro expansion.

Added trybuild tests to verify span propagation works correctly for both
simple and deeply nested patterns.