Auto merge of #13742 - lowr:fix/assoc-type-shorthand-with-gats, r=flodiebold

fix: only shift `BoundVar`s that come from outside lowering context

Fixes #13734

There are some free functions `TyLoweringContext` methods call, which do not know anything about current binders in scope. We need to shift in the `BoundVar`s in substitutions that we get from them (#4952), but not those we get from `TyLoweringContext` methods.

crates/hir/src/semantics.rs

@@ -1600,7 +1600,7 @@ impl<'a> SemanticsScope<'a> {
             self.db,
             def,
             resolution.in_type_ns()?,
-            |name, _, id| cb(name, id.into()),
+            |name, id| cb(name, id.into()),
         )
     }
 }

crates/hir/src/source_analyzer.rs

@@ -967,7 +967,7 @@ fn resolve_hir_path_(
                         db,
                         def,
                         res.in_type_ns()?,
-                        |name, _, id| (name == unresolved.name).then(|| id),
+                        |name, id| (name == unresolved.name).then(|| id),
                     )
                 })
                 .map(TypeAlias::from)