Warn on inert attributes used on bang macro invocation

These attributes are currently discarded.
This may change in the future (see #63221), but for now,
placing inert attributes on a macro invocation does nothing,
so we should warn users about it.

Technically, it's possible for there to be attribute macro
on the same macro invocation (or at a higher scope), which
inspects the inert attribute. For example:

```rust
#[look_for_inline_attr]
#[inline]
my_macro!()

#[look_for_nested_inline]
mod foo { #[inline] my_macro!() }
```

However, this would be a very strange thing to do.
Anyone running into this can manually suppress the warning.

compiler/rustc_lint/src/lib.rs

@@ -32,6 +32,7 @@
 #![feature(box_syntax)]
 #![feature(box_patterns)]
 #![feature(crate_visibility_modifier)]
+#![feature(format_args_capture)]
 #![feature(iter_order_by)]
 #![feature(iter_zip)]
 #![feature(never_type)]