Bring the LSP module up to date

[Isaac-Leonard]

Over the past few weeks I've been rapidly changing parts of the core compiler including key parts of the AST.
This unfortunately has brought the LSP module out of date to the point where it will not compile.
The required updates are minimal and should be made even easier now given the new utility methods on the AST.
This should be a relatively easy job although a lack of comments and documentation may make it harder than it should be.