Rollup merge of #70428 - Centril:move-to-mod, r=petrochenkov

`error_bad_item_kind`: add help text

For example, this adds:
```
    = help: consider moving the `use` import out to a nearby module scope
```
r? @petrochenkov @estebank

Fixes https://github.com/rust-lang/rust/issues/37205.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index cc88464d774..6b7a9ec658d 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -908,8 +908,10 @@ impl<'a> Parser<'a> {
 
     fn error_bad_item_kind<T>(&self, span: Span, kind: &ItemKind, ctx: &str) -> Option<T> {
         let span = self.sess.source_map().guess_head_span(span);
-        let msg = format!("{} is not supported in {}", kind.descr(), ctx);
-        self.struct_span_err(span, &msg).emit();
+        let descr = kind.descr();
+        self.struct_span_err(span, &format!("{} is not supported in {}", descr, ctx))
+            .help(&format!("consider moving the {} out to a nearby module scope", descr))
+            .emit();
         None
     }