KCL: Use named fields for KclError (#7321)

We've changed the unnamed field of `KclError` variants to a named called `details`.

To clarify: previously KCL errors looked like this:

```rust
pub enum KclError {
    Lexical(KclErrorDetails),
    Syntax(KclErrorDetails),
```

Now they look like this:

```rust
pub enum KclError {
    Lexical { details: KclErrorDetails },
    Syntax { details: KclErrorDetails },
}
```

This lets us more easily add fields to the errors. For example, in the UndefinedValue case, adding a field for what the undefined name was. This PR refactors the code to make my PR in https://github.com/KittyCAD/modeling-app/pull/7309 much easier.

Pure refactor, should not change any behaviour.

rust/kcl-lib/src/std/chamfer.rs

@@ -41,7 +41,7 @@ async fn inner_chamfer(
     // If you try and tag multiple edges with a tagged chamfer, we want to return an
     // error to the user that they can only tag one edge at a time.
     if tag.is_some() && tags.len() > 1 {
-        return Err(KclError::Type(KclErrorDetails::new(
+        return Err(KclError::new_type(KclErrorDetails::new(
             "You can only tag one edge at a time with a tagged chamfer. Either delete the tag for the chamfer fn if you don't need it OR separate into individual chamfer functions for each tag.".to_string(),
             vec![args.source_range],
         )));