fix: rust-lang#120878 Use param.name.indent().span if type parameter default exists.

change span.hi if exists default.

Diagnostic suggests adding : ?Sized in an incorrect place if a type parameter default is present

Author: OdenShirataki

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -2994,9 +2994,8 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             (s, " +")
         } else {
             (
-                if let GenericParamKind::Type { default: Some(default), synthetic: _ } = param.kind
-                {
-                    span.data().with_hi(default.span.lo() - rustc_span::BytePos(3))
+                if let GenericParamKind::Type { default: Some(_), synthetic: _ } = param.kind {
+                    param.name.ident().span
                 } else {
                     span
                 }