feat: annotations

[psteinroe]

adds a very simple Annotation service. the idea here is to annotate a statement using the lexed tokens. right now, it just returns whether or not the statement ends with a semicolon. in near future, I will also parse comments and their content so we can do #304, e.g.

-- postgrestools disable-next-line my-rule
select 1;

but to do that I will first need to adapt the splitter so that comments like that are included in the statement range :)

also replaced the root_id fn with From implementations