As someone who is firmly ( _firmly_ ) in the "nobody can write good manual memory management code" train, zig is probably a better fit than rust here - and this is one of the extremely rare circumstances where I would pick zig over rust.

Tree-sitter is written in C - the memory benefits of rust are completely moot. Zig also has a built-in C++ compiler, so you could generate the object file with a single toolset.