Update use_suggestion_placement.rs test, removing the FIXME that this PR fixes.

(There is another issue, in that the fixed output is not ideally indented, but
that is a pre-existing issue and should not block this PR.)

src/test/ui/resolve/use_suggestion_placement.fixed

@@ -14,13 +14,9 @@ mod m {
 }
 
 mod foo {
-    // FIXME: UsePlacementFinder is broken because active attributes are
-    // removed, and thus the `derive` attribute here is not in the AST.
-    // An inert attribute should work, though.
-    // #[derive(Debug)]
     use std::path::Path;
 
-#[allow(warnings)]
+#[derive(Debug)]
     pub struct Foo;
 
     // test whether the use suggestion isn't

src/test/ui/resolve/use_suggestion_placement.rs

@@ -10,11 +10,7 @@ mod m {
 }
 
 mod foo {
-    // FIXME: UsePlacementFinder is broken because active attributes are
-    // removed, and thus the `derive` attribute here is not in the AST.
-    // An inert attribute should work, though.
-    // #[derive(Debug)]
-    #[allow(warnings)]
+    #[derive(Debug)]
     pub struct Foo;
 
     // test whether the use suggestion isn't

src/test/ui/resolve/use_suggestion_placement.stderr

@@ -1,5 +1,5 @@
 error[E0412]: cannot find type `Path` in this scope
-  --> $DIR/use_suggestion_placement.rs:22:16
+  --> $DIR/use_suggestion_placement.rs:18:16
    |
 LL |     type Bar = Path;
    |                ^^^^ not found in this scope
@@ -10,7 +10,7 @@ LL |     use std::path::Path;
    |
 
 error[E0425]: cannot find value `A` in this scope
-  --> $DIR/use_suggestion_placement.rs:27:13
+  --> $DIR/use_suggestion_placement.rs:23:13
    |
 LL |     let _ = A;
    |             ^ not found in this scope
@@ -21,7 +21,7 @@ LL | use m::A;
    |
 
 error[E0412]: cannot find type `HashMap` in this scope
-  --> $DIR/use_suggestion_placement.rs:32:23
+  --> $DIR/use_suggestion_placement.rs:28:23
    |
 LL |     type Dict<K, V> = HashMap<K, V>;
    |                       ^^^^^^^ not found in this scope