Expose details of result column

In connectors like better-sqlite3: sqlite3_column_name and the origins of columns are exposed via Statement.columns, this is useful for analysing a statement.

I've written a connector which uses the Statement.columns method to automatically replace forgein key references with getters, I would like to bring this to the browser via sql.js but that information isn't exposed in this API, or in any other wasm API.

Would you be interested in adding a method similar to better-sqlite3's prepared statements? It's quite a niche thing but most server-side connectors impliment it, so people must be using it.

I have looked a little bit at sql.js' source code and I think I'll be able to impliment it myself and make a pull request, but I've never worked on C and JS in tandem so it would be a learning curve, I just haven't gone on that curve yet in case you think it's a dumb idea and you'll never merge it.

Thanks for your time.