Add test for non-crate-level inner attributes

Author: flip1995

tests/ui/cfg_attr_lint.rs

@@ -6,4 +6,12 @@
 #![cfg_attr(rustfmt, rustfmt_skip)]
 
 #[cfg_attr(rustfmt, rustfmt_skip)]
-fn main() {}
+fn main() {
+    foo::f();
+}
+
+mod foo {
+    #![cfg_attr(rustfmt, rustfmt_skip)]
+
+    pub fn f() {}
+}

tests/ui/cfg_attr_lint.stderr

@@ -6,5 +6,11 @@ error: `cfg_attr` is deprecated for rustfmt and got replaced by tool_attributes
   |
   = note: `-D clippy::deprecated-cfg-attr` implied by `-D warnings`
 
-error: aborting due to previous error
+error: `cfg_attr` is deprecated for rustfmt and got replaced by tool_attributes
+  --> $DIR/cfg_attr_lint.rs:14:5
+   |
+14 |     #![cfg_attr(rustfmt, rustfmt_skip)]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `#![rustfmt::skip]`
+
+error: aborting due to 2 previous errors