Tree diff and comparison for sipha syntax trees.
Compare two syntax trees by their emitted text (round-trip). Useful for tests (assert formatted output) or refactors (compare before/after).
Grammar tests with S-expressions
Use [assert_parse_eq] or the [assert_parse!] macro to compare a parsed
tree against an expected S-expression string (e.g. "(ROOT (EXPR (NUM \"1\")))").