Fields
target: []const u8,
target_must_resolve: []const u8,
prereq: []const u8,
incomplete_quoted_prerequisite: IndexAndBytes,
incomplete_target: IndexAndBytes,
invalid_target: IndexAndChar,
bad_target_escape: IndexAndChar,
expected_dollar_sign: IndexAndChar,
continuation_eol: IndexAndChar,
incomplete_escape: IndexAndChar,