Remove a duplicate space

rustfmt doesn't format `let ... else`.

compiler/rustc_typeck/src/check/fn_ctxt/suggestions.rs

@@ -637,7 +637,7 @@ fn try_suggest_return_impl_trait(
             })
             .collect::<Result<Vec<_>, _>>();
 
-        let Ok(where_predicates) =  where_predicates else { return };
+        let Ok(where_predicates) = where_predicates else { return };
 
         // now get all predicates in the same types as the where bounds, so we can chain them
         let predicates_from_where =