tree-sitter-lean — vendored grammar source.

Upstream:  https://github.com/Julian/tree-sitter-lean
Commit:    78b6e3d403b47d5cbac283db9dd48bc850441043
Sync date: 2026-05-20
License:   MIT (see LICENSE in this directory)

To re-sync from upstream, see docs/grammars/vendor-sync.md.

Vendoring scope: src/ only. parser.c is generated; do not edit by hand
(see vendor-sync.md). grammar.json and node-types.json are upstream
metadata kept alongside parser.c for parity with upstream layout.
