pub fn parse(source: &str) -> (Vec<Node>, Vec<char>)Expand description
Parse source into a top-level node list. Never fails — unclosed
groups/environments/math simply extend to end-of-input, matching
this crate’s tolerant-only philosophy (the Python side has a
separate strict-then-tolerant retry; this port only implements the
tolerant behavior, which is what most real documents already
resolve to after core/parser.py’s pre-neutralization).