2762e24a9c
This change brings back support for the unstable.Unmarshaler interface for tables and array tables, addressing issue #873. Key changes: - Changed UnmarshalTOML signature from (*Node) to ([]byte) to provide raw TOML bytes instead of AST nodes - Added RawMessage type (similar to json.RawMessage) for capturing raw TOML bytes for later processing - Updated handleKeyValuesUnmarshaler to reconstruct key-value lines from the parsed keys and raw value bytes - Added support for slice types implementing Unmarshaler (e.g., RawMessage) - Removed unused AST helper functions from unstable/ast.go The bytes-based interface allows users to: - Get raw TOML bytes for custom parsing - Delay TOML decoding using RawMessage - Implement custom unmarshaling logic for complex types Tests added for: - Table unmarshaler with various scenarios - Array table unmarshaler - Split tables (same parent defined in multiple places) - RawMessage usage - Nested tables and mixed regular fields