Fix whitespace in ?Sized structured suggestion

Author: estebank

src/librustc_trait_selection/traits/error_reporting/mod.rs

@@ -1655,7 +1655,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
                     {
                         let (span, separator) = match param.bounds {
                             [] => (span.shrink_to_hi(), ":"),
-                            [.., bound] => (bound.span().shrink_to_hi(), " + "),
+                            [.., bound] => (bound.span().shrink_to_hi(), " +"),
                         };
                         err.span_suggestion_verbose(
                             span,

src/test/ui/unsized3.stderr

@@ -31,8 +31,8 @@ LL | fn f4<X: T>(x: &X) {
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
 help: consider relaxing the implicit `Sized` restriction
    |
-LL | fn f4<X: T +  ?Sized>(x: &X) {
-   |            ^^^^^^^^^
+LL | fn f4<X: T + ?Sized>(x: &X) {
+   |            ^^^^^^^^
 
 error[E0277]: the size for values of type `X` cannot be known at compilation time
   --> $DIR/unsized3.rs:33:8