Currently it uses `walk_item` on some item kinds. For other item kinds
it visits the fields individually. For the latter group, this commit
adds `visit_attrs_vis` and `visit_attrs_vis_ident` which bundle up
visits to the fields that don't need special handling. This makes it
clearer that they haven't been forgotten about.
Also, it's better to do the attribute visits at the start because
attributes precede the items in the source code. Because of this, a
couple of tests have their output improved: errors appear in an order
that matches the source code order.
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
Consider comments and bare delimiters the same as an "empty line" for purposes of hiding rendered code output of long multispans. This results in more aggressive shortening of rendered output without losing too much context, specially in `*.stderr` tests that have "hidden" comments.
