Auto merge of #12572 - y21:mixed_attributes_style_style, r=llogiq

Move `mixed_attributes_style` to style

> It currently is in suspicious. I wouldn't say that the linted code is "most likely wrong or useless"
[...]
> 😅 I would still argue that this doesn't belong in the suspicious group, but rather in the style group.

These are some good points made [on zulip](https://rust-lang.zulipchat.com/#narrow/stream/257328-clippy/topic/mixed_attributes_style.20on.20outlined.20modules/near/429823328).

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changelog: Move [`mixed_attributes_style`] to the `style` category

clippy_lints/src/attrs/mod.rs

@@ -496,7 +496,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.78.0"]
     pub MIXED_ATTRIBUTES_STYLE,
-    suspicious,
+    style,
     "item has both inner and outer attributes"
 }