Fix is_relevant_impl.

It determines if a function should have any `inline` attributes checked.
For `ItemKind::Fn` it returns true or false depending on the details of
the function; for anything other item kind it returns *true*. This
latter case should instead be *false*. (In the nearby and similar
functions `is_relevant_impl` and `is_relevant_trait` the non-function
cases return false.)

The effect of this is that non-functions are no longer checked. But
rustc already disallows `inline` on any non-function items. So if
anything its a tiny performance win, because that was useless anyway.

Author: nnethercote

Diff for: src/tools/clippy/clippy_lints/src/attrs/utils.rs

@@ -24,7 +24,7 @@ pub(super) fn is_relevant_item(cx: &LateContext<'_>, item: &Item<'_>) -> bool {
     if let ItemKind::Fn { body: eid, .. } = item.kind {
         is_relevant_expr(cx, cx.tcx.typeck_body(eid), cx.tcx.hir_body(eid).value)
     } else {
-        true
+        false
     }
 }