lint: port box pointers diagnostics

Signed-off-by: David Wood <[email protected]>

Author: davidtwco

compiler/rustc_error_messages/locales/en-US/lint.ftl

@@ -289,3 +289,5 @@ lint-unused-allocation-mut = unnecessary allocation, use `&mut` instead
 
 lint-builtin-while-true = denote infinite loops with `loop {"{"} ... {"}"}`
     .suggestion = use `loop`
+
+lint-builtin-box-pointers = type uses owned (Box type) pointers: {$ty}

compiler/rustc_lint/src/builtin.rs

@@ -155,7 +155,7 @@ impl BoxPointers {
             if let GenericArgKind::Type(leaf_ty) = leaf.unpack() {
                 if leaf_ty.is_box() {
                     cx.struct_span_lint(BOX_POINTERS, span, |lint| {
-                        lint.build(&format!("type uses owned (Box type) pointers: {}", ty)).emit();
+                        lint.build(fluent::lint::builtin_box_pointers).set_arg("ty", ty).emit();
                     });
                 }
             }