Rollup merge of #45178 - Badel2:comma-after-struct, r=petrochenkov

Better error message for comma after base struct

#41834

This adds a better error for commas after the base struct:
```
let foo = Foo {
    one: 111,
    ..Foo::default(), // This comma is a syntax error
};
```

The current error is a generic `expected one of ...` which isn't beginner-friendly. My error looks like this:

```
error: cannot use a comma after the base struct
  --> tmp/example.rs:26:9
   |
26 |         ..Foo::default(),
   |         ^^^^^^^^^^^^^^^^- help: remove this comma
   |
   = note: the base struct expansion must always be the last field
```

I even added a note for people who don't know why this isn't allowed.

0 files changed, 0 insertions, 0 deletions