Clippy-fix explicit auto-deref

Seems like these can be safely fixed. With one, I was particularly
surprised -- `Some(pats) => &**pats,` in body.rs?

```
cargo clippy --fix -- -A clippy::all -D clippy::explicit_auto_deref
```

crates/hir-def/src/body.rs

@@ -372,7 +372,7 @@ impl Body {
     /// Retrieves all ident patterns this pattern shares the ident with.
     pub fn ident_patterns_for<'slf>(&'slf self, pat: &'slf PatId) -> &'slf [PatId] {
         match self.or_pats.get(pat) {
-            Some(pats) => &**pats,
+            Some(pats) => pats,
             None => std::slice::from_ref(pat),
         }
     }

crates/hir-def/src/body/scope.rs

@@ -47,7 +47,7 @@ pub struct ScopeData {
 impl ExprScopes {
     pub(crate) fn expr_scopes_query(db: &dyn DefDatabase, def: DefWithBodyId) -> Arc<ExprScopes> {
         let body = db.body(def);
-        let mut scopes = ExprScopes::new(&*body);
+        let mut scopes = ExprScopes::new(&body);
         scopes.shrink_to_fit();
         Arc::new(scopes)
     }