add ui test for #135903

fix error message

Author: TaKO8Ki

compiler/rustc_privacy/messages.ftl

@@ -25,7 +25,7 @@ privacy_in_public_interface = {$vis_descr} {$kind} `{$descr}` in public interfac
 
 privacy_item_is_private = {$kind} `{$descr}` is private
     .label = private {$kind}
-    .suggestion = consider using `..` to ignore fields with private types
+    .suggestion = consider using `..` to ignore the field with private type
 
 privacy_private_interface_or_bounds_lint = {$ty_kind} `{$ty_descr}` is more private than the item `{$item_descr}`
     .item_label = {$item_kind} `{$item_descr}` is reachable at visibility `{$item_vis_descr}`

tests/ui/privacy/private-pat-field-types.rs

@@ -0,0 +1,14 @@
+mod foo {
+    struct Bar;
+    pub enum Foo {
+        #[allow(private_interfaces)]
+        A(Bar),
+    }
+}
+fn foo_bar(v: foo::Foo) {
+    match v {
+        foo::Foo::A(_) => {} //~ ERROR type `Bar` is private
+    }
+}
+
+fn main() {}

tests/ui/privacy/private-pat-field-types.stderr

@@ -0,0 +1,14 @@
+error: type `Bar` is private
+  --> $DIR/private-pat-field-types.rs:10:21
+   |
+LL |         foo::Foo::A(_) => {}
+   |                     ^ private type
+   |
+help: consider using `..` to ignore the field with private type
+   |
+LL -         foo::Foo::A(_) => {}
+LL +         foo::Foo::A(..) => {}
+   |
+
+error: aborting due to 1 previous error
+