Split blocks and closures (#7075)

* Split closures and blocks

* Tests mostly working

* finish last fixes, passes all tests

* fmt

crates/nu-command/src/formats/from/nuon.rs

@@ -217,6 +217,12 @@ fn convert_to_value(
             "blocks not supported in nuon".into(),
             expr.span,
         )),
+        Expr::Closure(..) => Err(ShellError::OutsideSpannedLabeledError(
+            original_text.to_string(),
+            "Error when loading".into(),
+            "closures not supported in nuon".into(),
+            expr.span,
+        )),
         Expr::Binary(val) => Ok(Value::Binary { val, span }),
         Expr::Bool(val) => Ok(Value::Bool { val, span }),
         Expr::Call(..) => Err(ShellError::OutsideSpannedLabeledError(