lang: work on various things

- work on new world
  - add file db
  - source_file parsing
  - locs
- fix some test stuff

crates/lang/src/world/error.rs

@@ -0,0 +1,10 @@
+use std::path::PathBuf;
+
+use crate::{ast::ParseError, lst_parser::error::SyntaxError};
+
+use super::files::{FileId, Loc, OpenFileError};
+
+pub enum Error {
+    Syntax(Loc<ParseError>, SyntaxError),
+    OpenFileError(OpenFileError),
+}