Changed package.json so vscode extension settings have submenus
There are a lot of options that are a part of rust-analyzer, sometimes it can be hard to find an option that you are looking for. To fix this I have put all configurations into categories based on their names. I have also changed the schema in `crates/rust-analyzer/src/config.rs` to reflect this.
Currently for each generated entry the title is redeclared, this does function but I am prepared to change this if it is a problem.