`parse` command parses unused TSG rules

[robrix]

This could be considered a bug or a feature I suppose, but I was certainly surprised that an error in my .tsg prevented me from successfully running cargo run -p tree-sitter-stack-graphs-java -- parse file.java.

[hendrikvanantwerpen]

That's an interesting one. I agree that ideally it wouldn't fail. Butt the way the project is setup, I'm not sure it can easily be avoided.

The generic tree-sitter-stwck-graphs command that loads things from the file system wouldn't fail I think. But in the specialized tssg-java command, the language configuration is built up in memory before being used, and it's a little more eager.

[hendrikvanantwerpen]

Leaving a reference to https://docs.rs/lazy-init/latest/lazy_init/ here, in case we consider lazy rule parsing in language configurations.

[dcreager]

I think once_cell is preferred these days for all things lazily initialized.