Unnamed repository; edit this file 'description' to name the repository.
Rollup merge of #146849 - joshtriplett:macro-reduce-legacy-bang, r=petrochenkov
Reduce some uses of `LegacyBang`
- **Switch `dummy_bang` from `LegacyBang` to `Bang`**
- **mbe: Switch dummy extension used for errors from `LegacyBang` to `Bang`**
